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Solartron 1250 Operating Manual Set

Frequency response analyzer
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1250
Frequency Response
Analyzer
OPERATING MANUAL
1250

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  • Page 1 1250 Frequency Response Analyzer OPERATING MANUAL 1250...
  • Page 2 1250 Frequency Response Analyzer Solartron is a division of Solartron Group Ltd. Any reference to Schlumberger or Schlumberger Instruments (the name of the company until November 1993) implies no liability on the part of Schlumberger. Solartron Solartron Victoria Road, Farnborough...

  • Page 3: Declaration Of Conformity

    EN61010-1:1993 Safety requirements for electrical equipment for measurement, control and laboratory use. Accordingly the CE mark has been applied to this product. Signed For and behaIf of Solartron, a division of Solartron Group Limited Authority: Engineering Manager Date: December 1995 REGISTERED IN ENGLAND No.2852989.
  • Page 4 The equipment is designed solely for electronic measurement and should be used for no other purpose. Solartron Instruments accept no responsibility for accidents or damage resulting from any failure to comply with these precautions.
  • Page 5 1250 Frequency Response Analyzer SAFETY PRECAUTIONS (continued from previous page) SAFETY SYMBOLS For the guidance and protection of the user, the following safety symbols appear on the equipment: SYMBOL MEANING Refer to operating manual for detailed instructions of use. In particular, note the maximum voltages permissible at the input sockets, as detailed in the Specification.

  • Page 6: Table Of Contents

    Contents Section Page Chapter 1 General Information Introduction Basic measuring set-up The instrument essentials Additional facilities 1250 Variants Options Chapter 2 Installation Safety General Safety Precautions 2.2.1 Electromagnetic Compatibility Connecting the ac mains 2.3.1 Safety precautions: Earthing 2.3.2 Procedure Accessories Rack Mounting 2.5.1...
  • Page 7 Contents 1250 Frequency Response Analyzer 4.5.3 Generator Stop @ Key 4.5.4 Applications of the Stop @ Key 4.5.5 Generator Overload Protection Chapter 5 Making Measurements: The Analyzers Introduction Setting the [ANALYZER COMMON] Menu ∫ Time 5.2.1 5.2.2 Delay 5.2.3 Harmonic 5.2.4...
  • Page 8 1250 Frequency Response Analyzer Contents 9.1.2 Methods of Use 9.1.3 Method 1, With Analyzers Stopped 9.1.4 Method 2, With Analyzers Running 9.1.5 Using Variable with the Generator STOP @ Key 9.2 Amplitude Compression 9.2.1 Introduction 9.2.2 Principle of Operation 9.2.3 Generator Output Limit 9.2.4...
  • Page 9 Contents 1250 Frequency Response Analyzer 12.1.11 Terminator and Separator 12.6 12.2 The File 12.7 12.2.1 Introduction 12.7 12.2.2 Maximum File Size 12.7 12.2.3 Selecting File Size 12.7 12.2.4 Overwriting the Size of the File 12.7 12.2.5 Starting a File 12.8 12.2.6...
  • Page 10 13.14.1 RS423 Port, Device Control Characters 13.27 13.14.2 Procedure for Storing a Learnt Program Externally, via RS423 13.28 13.14.3 Procedure of Loading a Learnt Program into the 1250, Via RS423 Port 13.28 13.14.4 Procedure of Loading a Learnt Program into the 1250, Via GPIB Port 13.28...
  • Page 11 1250 Series Options 16.2 16.4 Connecting Up 16.4 16.4.1 Safety: Connecting the ac Mains 16.4 16.4.2 Connecting up the 1250-1251 Interface Bus 16.4 16.5 1251 Unit Identification Switches 16.5 16.5.1 Analyzer Channel Numbering 16.5 16.6 Manual Operation of the System 16.5...
  • Page 12 1250 Frequency Response Analyzer Contents 16.7.9 Dump Mode Format 16.10 16.8 1251 Multichannel Analyzer Specification 16.11 Chapter 17 Specification Index 1250...
  • Page 13 General Information Section Page Introduction Basic measuring set-up The instrument essentials Additional facilities 1250 variants Options CWB / 1260_Op / Issue 9...

  • Page 14: Chapter 1 General Information

    General Information 1250 Frequency Response Analyzer CWB / 1250_Op / Issue 9...

  • Page 15: Introduction

    Menu Terms INTRODUCTION The 1250 Frequency Response Analyzer measures the gain and phase characteristics of the system under test, when stimulated by a known sinusoid. Ease of use is provided by the touch-sensitive front panel keys. Many advanced features are incorporated, making full use of microprocessor technology.

  • Page 16: The Instrument Essentials

    General Information 1250 Frequency Response Analyzer THE INSTRUMENT ESSENTIALS The three main sections of the 1250 are: 1. A Generator which produces a sinusoidal, square, or triangular-wave electrical stimulus for the system on test. 2. Two analyzers which measure the response to the stimulus at two points in the system, enabling either of the following to be calculated and displayed: a) Single Point measurements (i.e., the absolute voltage of either Channel, and its...

  • Page 17: Additional Facilities

    The results may also be stored within the instrument for further processing. Additionally, results may be passed to a plotter or computer. ADDITIONAL FACILITIES These are shown in Fig. 1.5 Figure 1.5 - 1250 Block Schematic CWB / 1250_Op / Issue 9...
  • Page 18 For example, the major programmable sections of the 1250 are each controlled by a menu. If the GENERATOR MENU key is pressed, the lower half of the display will assign titles to the five soft keys as shown in Fig.

  • Page 19: 1250 Variants

    1250 Frequency Response Analyzer Menu Terms 1250 VARIANTS The 1250 is available in several versions, as shown in the table: Model Number of Front Panel Compliant with Notes Channels control European EMC Regulations 1250A 1250B 1250E 1250N Low impedance generator output...

  • Page 20: Options

    General Information 1250 Frequency Response Analyzer OPTIONS All these are controllable from the 1250 Keyboard, as are the GPIB and Serial Interface. 1. Synchroniser (12501A)*: enables the 1250 to be synchronised to an external source. 2. Modulator/Demodulator (1250A): enables the 1250 to be directly interfaced with systems that require ac carrier inputs, or which produce ac carrier outputs.

  • Page 21: Cwb / 1260_Op / Issue 9

    Alpha-numeric display SI1250 self test FREQUENCY RESPONSE ANALYZER SELECT CLEAR VARIABLE STATUS VIEWFILE LOCAL BREAK ENTER Soft keys DISPLAY/ MENU MENU MENU MENU FUNCTION LEARN GENERATOR ANALYSER SWEEP PROGRAM PLOTTER STOP START/ DATA PAUSE/ STOP START STOP SINGLE RECYCLE STOP HOLD STOP PLOT...
  • Page 22 General Information 1250 Frequency Response Analyzer Note: The rear panel shown is for 1250E or 1250B. Other versions of 1250 may have a slightly different appearance. Figure 1.8 - Rear panel layout 1-10 CWB / 1250_Op / Issue 9...

  • Page 23: Installation

    1250 Frequency Response Analyzer Installation Installation Section Page Safety General Safety Precautions 2.2.1 Electromagnetic Compatibility Connecting the ac mains 2.3.1 Safety precautions: Earthing 2.3.2 Procedure Accessories 2.5 Rack Mounting 2.5.1 Rack Dimensions 2.5.2 Ventilation 2.5.3 Fitting Telescopic Slide Mounting Kit 12505B (Accuride) 2.5.4...

  • Page 24: Safety

    5. Any interruption of the earth connection (inside or outside the 1250) is prohibited. 6. When the 1250 is connected to its supply the opening of covers or removal of parts could expose live conductors. The 1250 should be disconnected from all voltage sources before it is opened for any adjustment, replacement, maintenance or repair.

  • Page 25: Electromagnetic Compatibility

    When used as described in this manual the 1250B, 1250E and 1254A models meet the requirements of the EMC Directive, (see Specification in Chapter 17). The 1250 must not be operated with the inner metal screens removed and any replacement components must be of the correct type.

  • Page 26: Connecting The Ac Mains

    If the user already has available a supply cable terminated with an IEC socket, then this can be plugged directly into ac supply plug on the 1250. It should be ensured. however, that the socket is correctly wired, as shown in Fig. 2. 1.

  • Page 27: Accessories

    (Option 12505B, or 12505C for U.S.A.) is also packed. RACK MOUNTING The 1250 can be rack mounted in two ways: either by using fixed rails in the rack to support the underside of the case, or by using telescopic slides to support the 1250 and allow easy withdrawal for servicing.

  • Page 28: Rack Dimensions

    760mm (30 ins) deep X 485mm (19 ins) wide for telescopic slide mounting (using either kit) 2.5.2 VENTILATION Ensure that the rack in which a 1250 is mounted has adequate ventilation, either by an extractor fan or by having the rear of the rack open. 2.5.3 FITTING TELESCOPIC SLIDE MOUNTING KIT 12505B (ACCURIDE) 1.
  • Page 29 Fit the rack ears in place of the finisher trim, using the same fixings. The ears may he fitted as illustrated, or with their flanges facing the rear of the 1250, which causes the unit to stand out further in the rack, allowing use of racks too shallow for normal mounting.
  • Page 30 Adjustable Rear Brackets (two off) Fit one rear bracket to each outer member, but do not fully tighten the screws until the 1250 is fitted into the rack (step 6). Figure 2.5 - Fitting a rear bracket CWB / 1250_Op / Issue 9A...
  • Page 31 1250 Frequency Response Analyzer Installation d. Fixed Front Brackets together with Support Brackets (two off each) Figure 2.6 - Fitting a front bracket and support bracket 4. Fit the M6 caged nuts for outer slide member and rack ear fixing into the rack in positions shown in Fig.
  • Page 32 Tighten the M5 screws securing each member until it is held moderately firmly in the rack, approximately in the centre of its travel. The members must, however, be free enough to take up any adjustment when the 1250 is first fitted into the rack.

  • Page 33: Fitting Telescopic Slide Mounting Kit 12505C (Jonathan)

    6. Finally, fit the 1250 into the rack, as follows: a. Offer the 1250 up to the rack and feed the inner telescopic slide members into the outer members, pushing the unit into the rack until the locking catches engage and lock.
  • Page 34 Rack Ears (2 off) Fit the rack ears in place of the finisher trim, using the same fixings. The flanges must face the rear of the 1250. b. Slide Mounting Bar Screw the bar to the chassis in the former position of the handle, using the four M4x12 countersunk screws provided.
  • Page 35 1250 Frequency Response Analyzer Installation Figure 2.10 - Fitting rack ears, slide mounting bar and replacement cases 2-13 CWB / 1250_Op / Issue 9A...
  • Page 36 Installation 1250 Frequency Response Analyzer 2-14 CWB / 1250_Op / Issue 9A...
  • Page 37 Switching On and Initialising 1250 Frequency Response Analyzer Switching On and Initialising Section Page Switch On Initialising Resetting AMK / 1250 / 3...

  • Page 38: Switch On

    Figure 3.1 - Power-up Message a. This signifies that the 1250 has correctly remembered the settings for the Generator etc., from the last time it was used. Also, any Learnt programs are still available, and readings stored in the File have not been corrupted.

  • Page 39: Initialising

    Display will be as shown in Fig. 3.4. Figure 3.4 The 1250 is now in an identical state to that shown in Fig. 3.2, except that Learnt Programs 10 to 18 will also have been erased if the keyswitch is in the Supervisor position.

  • Page 40: Resetting

    RESET soft key instead of INIT. When resetting is complete, the Display will be as shown in Fig. 3.5. Figure 3.5 For details of other “self test” functions, see Chapter 14 Section 2 Self Test. AMK / 1250 / 3...
  • Page 41 Making Measurements: The Generator Section Page Simple Measurements Setting the Generator 4.2.1 Introduction 4.2.2 Setting the Generator Menu 4.2.3 Waveform 4.2.4 Frequency 4.2.5 Clear 4.2.6 Amplitude 4.2.7 Bias 4.2.8 Modulated Carrier Checking Generator Settings: Using the Status Displays Starting the Generator 4.4.1 Generator Start Key 4.4.2...

  • Page 42: Chapter 4 Making Measurements: The Generator

    1250 Frequency Response Analyzer SIMPLE MEASUREMENTS As the 1250 is so versatile, very comprehensive measuring sequences can be set up. Before attempting these however, it is recommended that the user acquire familiarity with the basic controls by making a few simple measurements first. Refinements such as Sweep, Recording of Data, Scaling of readings etc.

  • Page 43: Frequency

    Successively operate the SELECT key until the chosen word appears in the square brackets. Press ENTER, the new command will not be accepted by the 1250 until ENTER is pressed. The Display will revert to that shown in Fig. 4. 1.

  • Page 44: Clear

    CHECKING GENERATOR SETTINGS: USING THE STATUS DISPLAYS To cheek that the Generator, or any other section of the 1250, has been set up correctly, the user could step through all the Menus again. However, a better method is to use the STATUS key, as described in Chapter 11.

  • Page 45: Starting The Generator

    GENERATOR WAVEFORM STARTING POINT For most applications of single sinewave measuring techniques, the Generator waveform starting point is not critical. The power-up reset that occurs when the 1250 is switched on, and the initialising routine both ensure that the Generator waveform commences at 0°...

  • Page 46: Generator Stop @ Key

    Stop point, it will halt there and stay until START is pressed again (unless the 1250 is initialised, or switched on and off again in the meantime). When START is operated again, the STOP @ command is cancelled, and the Generator will continue running from the cardinal point at which it had been instructed to stop.

  • Page 47: Generator Overload Protection

    The 1250N (low source impedance) uses feedback within the power amplifier to limit the current to ∼300mA into a short-circuit. The 1250 relies on its higher source impedance (50 Ω) to limit the current to a similar value. No error message is displayed.
  • Page 48 Auto ∫ 5.2.5 5.2.6 Applications of Auto Integration Setting Individual Analyzers 5.3.1 Range 5.3.2 Demod 5.3.3 Coupling 5.3.4 Input Measurement Start Stopping the Analyzer; Stop and Break Keys Changing Menus during Recycle Measurement Start Point 5.7.1 Implementation of Delay AMK/1250/3...

  • Page 49: Chapter 5 Making Measurements: The Analyzers

    Making Measurements: The Analyzers 1250 Frequency Response Analyzer INTRODUCTION Having completed the Generator Menu, the Analyzers may now be set up. Channels 1 and 2 are connected to Analyzers 1 and 2 respectively. The numbering of any additional Analyzers is explained in Chapter 16, The 1251 Multichannel Analyzer System.

  • Page 50: Delay

    5.2.3 HARMONIC The 1250 can be set to analyze the response of the system under test at any harmonic of the fundamental up to the 16th, provided that the frequency of the harmonic does not exceed 65.535 kHz. Enter the required harmonic number, between 1 and 16, in the round brackets in the Display.

  • Page 51: Order

    The maximum time that the user is prepared to allow should be entered using the ∫ TIME key. If the 1250 has just been initialised, and no new value is entered here, the default value is automatically increased when AUTO ∫ is enabled, to the longer of 3 cycles or 1 second.
  • Page 52 1250 Frequency Response Analyzer Making Measurements: The Analyzers Auto-integration can also be used to reduce sweep time when the signal-to-noise ratio varies widely across the swept spectrum. Consider the points plotted in Fig. 5.2. Figure 5.2 - Plot of readings from a sweep measurement Either side of the band marked "noise", a fairly clear curve is indicated, as represented...

  • Page 53: Setting Individual Analyzers

    Pressing this key offers the user a choice of several fixed ranges from 30mV to 300V. See the full Specification, Chapter 17 for details of these. There is also an auto-ranging feature whereby the 1250 itself selects the range which will produce an accurate result with the best possible resolution. Measurements start on the most sensitive range and as soon as an overload is detected, the measurement is terminated, the range is changed and the measurement restarted.

  • Page 54: Measurement Start

    The Status information will follow the sequence given in 1c. The Running Display When the 1250 has completed a measurement, the Display will resemble Fig. 5.4. Figure 5.4 - The Running Display The top left-hand number shows the frequency at which the measurement was made, in this case 504 Hz.

  • Page 55: Stopping The Analyzer; Stop And Break Keys

    The Generator and Analyzer do not have to be stopped in order to change the Menus. Any change that is entered will be held until the 1250 has completed the current measurement. The alteration will then be implemented and the next measurement made according to the new setting.
  • Page 56 6.9.1 Introduction 6.9.2 Commands Which Produce “Sweep Stop” Status 6.9.3 Commands Which Produce “Sweep Idle” or “Hold” Status 6.10 Changing Parameters in Mid-Sweep 6.11 Harmonic Sweep 6.11.1 Introduction 6.11.2 Perfoming a harmonic Sweep 6.11.3 Error 21 6.11.4 Sweep Termination Conditions CHFR/1250/2...

  • Page 57: Chapter 6 The Sweep Facility

    A special form of Harmonic Sweep can also be performed, as described separately. LOGARITHMIC SWEEP The 1250 offers four ways of setting a logarithmic sweep, selected by soft keys. In each case, the successive steps in Generator frequency are related by constant ratios, defined as follows.

  • Page 58: Setting Up A Logarithmic Or Linear Sweep

    1250 Frequency Response Analyzer The Sweep Facility SETTING UP A LOGARITHMIC OR LINEAR SWEEP 1. Press the Generator, Analyzer and Sweep STOP keys. 2. Use the Generator Menu to set the required amplitude, bias, waveform etc. The Generator frequency need not be altered, as the Sweep controls will over-ride any existing setting.

  • Page 59: End Of Sweep Conditions

    The Sweep Facility 1250 Frequency Response Analyzer END OF SWEEP CONDITIONS On the completion of a sweep, the Status of the Analyzers and Sweep controls will have reverted to STOP, but the Generator will keep running at the last frequency commanded.

  • Page 60: Commands Which Produce "Sweep Idle" Or "Hold" Status

    1250 Frequency Response Analyzer The Sweep Facility 6.9.3 COMMANDS WHICH PRODUCE "SWEEP IDLE” OR "HOLD" STATUS a. ANALYZER SINGLE. The Analyzers will complete the current measurement, display a valid reading and stop. If SINGLE is pressed again, the Generator will step on to the next frequency in the sweep, and a new measurement will be made.

  • Page 61: Perfoming A Harmonic Sweep

    The Sweep Facility 1250 Frequency Response Analyzer 6.11.2 PERFORMING A HARMONIC SWEEP 1. STOP the Generator, Analyzer and Sweep. 2. Use the GENERATOR MENU keys to set the required fundamental frequency. 3. Set up the Analyzer Menu. Any Harmonic number entered, other than 1, will be over-ridden by the Harmonic Sweep command.
  • Page 62 The Display Menu and Mini Status Section Page Introduction Sources Co-Ordinates Mini Status Display CHFR/1250/2...

  • Page 63: Introduction

    The Display Menu and Mini Status 1250 Frequency Response Analyzer INTRODUCTION In the default state the Display uses Channel 1 Analyzer as its source, and presents the readings in cartesian (a+jb) form. By using the DISPLAY/PLOTTER MENU key, in conjunction with its associated soft keys, different sources and co-ordinates can be selected.

  • Page 64: Sources

    [Ch ( )] and entering the required Channel number in the round brackets. To avoid confusion, the user should not enter a 1 or a 2 here. If the 1250 sees a 1 or a 2 in the round brackets, it automatically selects Channel 1 or Channel 2 respectively, and the STATUS display will show Ch 01 or Ch 02 as the chosen Source.

  • Page 65: Mini Status Display

    The Display Menu and Mini Status 1250 Frequency Response Analyzer MINI STATUS DISPLAY When the bottom line of the Display appears in square brackets, as Fig. 7.2 below, the SELECT key can be used to call up the following status messages. Where one of several different messages may follow a title, they are shown in the form: /IDLE/RUN/NONE.

  • Page 66: Menu Summary

    Menu Summary Section Page Introduction AMK/1250/1...
  • Page 67 FREQ soft key is 1E-5 to 65535 Hz, as shown in the table. d. If just initialised, the 1250 displays "not entered" in front of the round brackets; otherwise the last ENTERed value is displayed. When "not entered" appears, the default value is operative.
  • Page 68 1250 Frequency Response Analyzer Menu Summary 1250 MENU SUMMARY MENU SELECTION SOFT KEYS GENERATOR [GENERATOR] FREQ AMPL BIAS WAVEFORM (100 Hz) (0 V) (0 V) [ sine ] 1E-5 to 0 to -10.23 to [square ] [carrier 1 on] 65535 Hz 10.23V*...
  • Page 69 Menu Summary 1250 Frequency Response Analyzer MENU SELECTION SOFT KEYS DISPLAY/ [PLOTTER X-AXIS] ITEM MINIMUM MAXIMUM ORIGIN PLOTTER (contd.) -1E18 to 1E18 θ [log r in dB] [ f in Hz ] [log f in Hz] [PLOTTER Y-AXIS] (Soft keys and values as for [PLOTTER X-AXIS]...
  • Page 70 Method 2, With Analyzers Running 9.1.5 Using Variable with the Generator STOP @ Key 9.2 Amplitude Compression 9.2.1 Introduction 9.2.2 Principle of Operation 9.2.3 Generator Output Limit 9.2.4 Setting the Menu 9.2.5 Error 84 9.2.6 Use of the File AMK/1250/2...

  • Page 71: Introduction

    Additional Generator Controls 1250 Frequency Response Analyzer THE VARIABLE KEY 9.1.1 INTRODUCTION This mode of control enables the user to vary the Generator settings, whilst observing the effect on the object-under-test. By this means, for example, the optimum position of a mechanical device may be determined empirically, or an electrical resonance identified by observing the changing Display readings.

  • Page 72: Method 2, With Analyzers Running

    Note 1. The frequency shown here as "x.xxxx" is the last frequency entered. This will be zero if the 1250 has just been initialised. To enter a new initial frequency upon which the VARIABLE controls can operate, use the Generator Menu keys as described in Chapter 4.

  • Page 73: Using Variable With The Generator Stop @ Key

    Additional Generator Controls 1250 Frequency Response Analyzer When VARIABLE is pressed, the Display will change to just show: VARIABLE. [freq] as before. When the required Generator parameter has been entered, the Display will resemble Fig. 9.3. Figure 9.3 - Typical Display with VARIABLE pressed and Analyzers running.

  • Page 74: Amplitude Compression

    The user defines the nominal voltage which is to be maintained at this point and the percentage error that can be tolerated. For example, if 1 volt ± 25% is specified, the 1250 will attempt to hold the monitored voltage between the levels 0.75 and 1.25 volts.
  • Page 75 Additional Generator Controls 1250 Frequency Response Analyzer Figure 9.5 - Amplitude Compression flow diagram. AMK/1250/2...

  • Page 76: Generator Output Limit

    Additional Generator Controls In order to hold the Intermediate Signal as closely as possible to its target value, and not merely within the tolerance band, the 1250 computes and applies any correction necessary to the Generator Output after displaying each reading.

  • Page 77: Setting The Menu

    Section 9.2.2 describes how ERROR 84 will be displayed if the corrected Generator output still yields a wrong signal level at the monitored point. This can occur if the 1250 bases its correction ratio calculation on unsuitable data, and may necessitate increasing the % ERROR value.
  • Page 78 Facilities For More Complex Measurements Section Page 10.1 The Function Key 10.2 10.1.1 Introduction 10.2 10.1.2 Angle Information 10.3 10.1.3 Multiplication Factors: Xω 10.4 10.1.4 Scaling 10.5 10.1.5 Limits 10.6 10.1.6 Function Key Summary 10.7 10.2 Data Flow Schematic 10.8 10-1...

  • Page 79: Chapter 10 Facilities For More Complex Measurements

    Facilities For More Complex Measurements 1250 Frequency Response Analyzer 10.1 THE FUNCTION KEY 10.1.1 INTRODUCTION The FUNCTION key enables the result of a measurement to be processed in a variety of ways, before it appears as a reading: 1. The user may choose from several angle conventions, based on degrees or radians.

  • Page 80: Angle Information

    1250 Frequency Response Analyzer Facilities For More Complex Measurements 10.1.2 ANGLE INFORMATION Having pressed FUNCTION, followed by the ANGLE soft key, SELECT and ENTER either "degree" or "radian". Each of these offers four choices of presentation, as illustrated in Fig 10.1. ENTER the required choice.
  • Page 81 Facilities For More Complex Measurements 1250 Frequency Response Analyzer 10.1.3 MULTIPLICATION FACTORS: x ω ω Pressing the x ω soft key gives the user a choice of four multiplication factors, plus the default state of "x unity" which is the "off" condition. The four choices are: 1.

  • Page 82: Scaling

    1250 Frequency Response Analyzer Facilities For More Complex Measurements Figure 10.3 - Use ofMultiplication Factors 10.1.4 SCALING Pressing the SCALE soft key gives the user a choice of three scaling factors whereby the result of a measurement can be divided by a vector. There is also a default state of "divide by unity", which is the "off”...

  • Page 83: Limits

    Facilities For More Complex Measurements 1250 Frequency Response Analyzer 10.1.5 LIMITS The LIMIT soft key enables the user to assign a pair of values, called Upper and Lower Limits, to any one of five parameters. The measured results can then be compared to these values, results between the Limits being defined as Passes, those outside as Fails.

  • Page 84: Function Key Summary

    1250 Frequency Response Analyzer Facilities For More Complex Measurements 10.1.6 FUNCTION KEY SUMMARY Soft Key Display Displayed Choices ANGLE ANGLE [degree] CONVENTION [-180 to +180ant. clk] (Default State} ↑ CONVENTION [0 to 360 ant. clk} SELECT and (SELECT and CONVENTION [-360 to 0 ant. clk}...

  • Page 85: Data Flow Schematic

    Facilities For More Complex Measurements 1250 Frequency Response Analyzer 10.2 DATA FLOW SCHEMATIC Each stage is represented by a box. Where the box has two sections, the upper contains the title of the facility and the lower shows the relevant Front Panel key.
  • Page 86 Additional Displayed Information Section Page 11.1 The Status Key 11.2 11.1.1 Introduction 11.2 11.1.2 Using the Key 11.2 11.1.3 Main Status 11.3 11.1.4 Other Status 11.5 11.1.5 Printed Record 11.8 11.2 Error Codes 11.9 11.2.1 Introduction 11.9 11.2.2 Error Codes: Summary 11.9 11.3 Error Codes: Details 11.11...

  • Page 87: Chapter 11 Additional Displayed Information

    1250. Quantities displayed in lower case are usually those which the user has entered, whereas those in upper case indicate the state of the instrument. In the details that follow, where one of several different states may appear after a particular heading, all the possible states are listed in the form: RUN/STOP/IDLE/etc.

  • Page 88: Main Status

    1250 Frequency Response Analyzer Additional Displayed Information 11.1.3 MAIN STATUS Soft Key Page Display 1 GENERATOR RUN/STOP/FAULT WAVEFORM sine/square/triangle CARRIER NONE/LO/on MODoff/1on/2on Notes: GENERATOR FAULT indicates that the Generator board is missing. CARRIER NONE indicates that no Modulator/Demodulator board is fitted.

  • Page 89: Main Status

    Additional Displayed Information 1250 Frequency Response Analyzer MAIN STATUS ( cont. Soft Key Page Display SWEEP 1 SWEEP STOP/IDLE/HOLD/RUN TYPE harm up/lin/up/ lin down/log up/log down 2 F. MIN (Hz) F. MAX (Hz) value value value * For LOG: st/dec or st/oct or st/swp or ratio For LIN: st/swp or step (Hz) where st = step, dec = decade, oct = octave, swp = sweep.

  • Page 90: Other Status

    1250 Frequency Response Analyzer Additional Displayed Information 11.1.4 OTHER STATUS Soft Key Page Display SYNC 1 SYNC. NONE/IDLE/WAIT/STABLE/LOCKED/FAULT followed by a single digit fault identifier. Further pages appear only if synchroniser option is fitted. 2 TRIG LEVEL RATIO SLOPE COUPLING...
  • Page 91 BUSY indicates that it is engaged on some other activity. Pause indicates that it is waiting for a user input. The three position keyswitch on the rear panel of the 1250 allows the user to set the operating mode to 'Supervisor', 'Operator' or 'Normal'.
  • Page 92 1250 Frequency Response Analyzer Additional Displayed Information µ µ P (cont.) Page Display LAST UPPER LOWER LIMIT value value This page can be used to determine the limits which apply to the current parameter being entered, as an alternative to looking it up in the full specification.

  • Page 93: Printed Record

    Additional Displayed Information 1250 Frequency Response Analyzer GPIB (cont.) Soft Keys Page Display 2 GPIB SER. POLL PAR. POLL CONTROL 8 digits, consisting A number local/ of a set of “flags” from 0 to 8 remote/ and a “service” 0 = disabled loc + llo/ bit.

  • Page 94: Error Codes

    1250 Frequency Response Analyzer Additional Displayed Information 11.2 ERROR CODES 11.2.1 INTRODUCTION The Error Codes fall into two main categories: a. Those which explain why the instrument has stopped; some of these are warnings rather than errors. b. Those which explain why the instrument will not respond to a new command.
  • Page 95 Additional Displayed Information 1250 Frequency Response Analyzer ERROR CODES: SUMMARY (cont.) Group 4 = Learnt Program, File and Variable Line number not found Jump outside Program mode Attempt to step variable out of range File empty Illegal File access Illegal File size entry...

  • Page 96: Error Codes: Details

    For example: RA 1, 3 means set the Analyzer voltage range (RA), of Analyser 1, to Range 3. When the 1250 sees RA, it expects to see two other pieces of numeric information following. If it only sees one, this is detected and flagged as an Argument mismatch.

  • Page 97: Group 1. Errors Pertaining To The Learnt Program

    A". This is only allowed under special circumstances, as described in Chapter 12. 16 Program Check Sum error. Learnt programs are stored in the 1250 memory; a check sum is calculated and stored with the program data. Before a stored program can be operated upon, a new check sum is calculated, and compared with the original.

  • Page 98: Group 4. Learnt Program, File And Variable

    11.3.7 GROUP 5. MISSING BOARDS An Error Code number in this Group will be displayed only if the 1250 is commanded to perform an operation requiring a board or boards which are not fitted, e.g. if Modulation is programmed but no Mod/Demod board is present.

  • Page 99: Group 6. Illegal I/O Manipulation

    11.3.8 GROUP 6. ILLEGAL I/O MANIPULATION 60 Changing I/O Device during Learn sequence. This error indicates that the 1250 was in the Learn mode prior to the command which attempted to change the I/O device. As a result of this command, not only has the I/O device been changed; but the Learnt Program has also been terminated automatically.

  • Page 100: Group 8. Measurement Validity Is Suspect

    1250 Frequency Response Analyzer Additional Displayed Information 11.3.10 GROUP 8. MEASUREMENT VALIDITY IS SUSPECT Mainly covers conditions under which a valid measurement may not have been achieved. The 1250 will display a reading accompanied by the appropriate warning code number. 11-15 AMK/1250/3...

  • Page 101: The Data Output Key

    12.17 12.4.6 Performing a Plot 12.18 12.4.7 Bode and Nyquist Plots 12.19 12.4.8 Adjusting the Plotting Field to suit Preprinted Chart Paper 12.20 12.4.9 Pen Selection with two Pen Plotters 12.21 12.4.10 Plotting Data from the File 12.21 12-1 SH/1250/3...

  • Page 102: Chapter 12 Recording, Learning And Storing Facilities 12.1 The Data Output Key

    Recording, Learning and Storing Facilities 1250 Frequency Response Analyzer 12.1 THE DATA OUTPUT KEY 12.1.1 INTRODUCTION The DATA OUTPUT key accesses three menu pages, which appear in the order: [DATA OUTPUT], [FORMAT], and [GPIB CONFIGURE]. These are described in the following sections, and summarised for quick reference in Chapter 8.
  • Page 103 The display can be regained by pressing any front panel key which causes entry into a menu. The Display can be switched off when using the 1250 as part of a system, so that data may be transferred more rapidly and also to prevent the display from burning out.
  • Page 104 HEADING and REFORMAT states, when one of the menu changes listed in Section 12.1.6 is made. Note: After SINGLE or RECYCLE, or REFORMAT 'on', a result without headings is output in all cases (apart from the initial set of headings and results output by the 1250). DATA OUTPUT MENU CHANGE...
  • Page 105 1250 Frequency Response Analyzer Recording, Learning and Storing Facilities 12.1.6 MENU CHANGES ACTIVATING THE HEADING AND REFORMAT FUNCTIONS HEADING and REFORMAT may be initiated by changes to any of the following menus: a. Any FUNCTION menu b. The [DATA OUTPUT] menu c.

  • Page 106: Serial Poll

    An integer from 1 to 8 is input (between the round brackets) to define which of the eight GPIB data lines is to be used by the 1250 to give a Parallel Poll response, indicating whether it is requesting service or not.

  • Page 107: The File

    12.2 THE FILE 12.2.1 INTRODUCTION The File is a section of memory in the 1250 which can he used to store results from measurements sequences, for later recall and further processing if required. The 1250 retains this File for at least 100 hours after power is switched off.

  • Page 108: Starting A File

    Recording, Learning and Storing Facilities 1250 Frequency Response Analyzer 12.2.5 STARTING A FILE Readings can be stored in the File as follows: 1. Press DATA OUTPUT 2. Press soft key FILE 3. SELECT and ENTER the required mode, e.g. FILE [pass] 4.

  • Page 109: Learnt Programs

    READING FROM THE FILE (cont.) This indicates that the 1250 has taken 181 readings, of which 168 were of the specified type to be filed e.g. FILE [fail]. Only 99 readings have been filed in this example, as this was the current maximum capacity of the File.

  • Page 110: Learning A Program: From An External Device

    Error 01 ('unknown command') may be flagged when the line is entered. 3. To terminate the program enter the command: The Learnt Program is now in the 1250's memory and may be executed or edited from either the front panel or from the external device.

  • Page 111: Executing A Program

    EP 2 to ensure that program 2 can execute itself. 12.3.5 EDITING A PROGRAM: FROM THE FRONT PANEL From the 1250 front panel, program lines may be displayed singly, completely deleted, or new lines inserted. Editing is also possible via a peripheral device connected to the GPIB or RS423 ports.

  • Page 112: Editing A Program: From An External Device

    To enter Edit Mode for program number 'n', send the command *En from the external device. The message: EDIT MODE, and the first program line are sent by the 1250 to the device (e.g. printer). b. To step to the next line of the program, send the command *F. To step backwards to the previous line, send *B.

  • Page 113: Program Pause/Continue Key

    ERROR14@00. For programs which have been learnt via the 1250 front panel. Specific line numbers (up to 98 maximum) may be displayed with the error message if the program was input via the GPIB or RS423 ports.

  • Page 114: Y Plotter

    Listen Only mode (or addressed to Listen by using a suitable Controller), and the 1250 must be switched to TALK ONLY using the switch on the rear panel (or be addressed to Talk by using a suitable Controller).

  • Page 115: The [Plotter Common] Menu

    With TEXT 'off', the plotted axes appear without any annotation. Leave TEXT at its default state for this example plot. Figure 12.2 - Example plot: 1250 square wave harmonics d. GRID With GRID 'off' (the default state) during axes plotting, the divisions along the X and Y directions of the graph borders are marked by short lines only.

  • Page 116: The [Plotter X-Axis] And [Plotter Y-Axis] Menus

    Recording, Learning and Storing Facilities 1250 Frequency Response Analyzer 12.4.4 THE [PLOTTER X-AXIS] AND [PLOTTER Y-AXIS] MENUS Set up the [PLOTTER X-AXIS] and [PLOTTER Y-AXIS] pages of the DISPLAY/ PLOTTER menu. The four soft keys and their selections are identical for both pages:...

  • Page 117: The [Plotter Scaling] Menu

    With SCALE set to [ fixed ], the default state, the size of the plotting field is matched by the 1250 to the paper size selected (A3 or A4); the shape (square or rectangular) is determined solely by the ITEM choice (see Section 12.4.4a above).

  • Page 118: Performing A Plot

    For the present example plot, leave SCALE at its default state i.e. [ fixed ]. 12.4.6 PERFORMING A PLOT Connect a suitable plotter to the appropriate port of the 1250, and set mode switches to their correct positions (Section 12.4.1 above explains this).

  • Page 119: Bode And Nyquist Plots

    1250 Frequency Response Analyzer Recording, Learning and Storing Facilities 12.4.7 BODE AND NYQUIST PLOTS Different plot types may be obtained by selecting appropriate items via the ITEM soft keys in the (PLOTTER X-AXIS] and [PLOTTER Y-AXIS] menus. See Section 4.4 above.

  • Page 120: Adjusting The Plotting Field To Suit Preprinted Chart Paper

    In this case the [PLOTTER SCALING] page of the DISPLAY/PLOTTER menu can be used, in conjunction with the VARIABLE key. Assuming a suitable plotter has been set up and connected to the 1250, and the DEVICE soft key of the (PLOTTER COMMON] menu has been correctly set, proceed as follows: 1.

  • Page 121: Pen Selection With Two Pen Plotters

    Recording, Learning and Storing Facilities 12.4.9 PEN SELECTION WITH TWO-PEN PLOTTERS With two-pen plotters, pen 1 is automatically selected by the 1250 if the X-axis ORIGIN is set to be the same as the X-axis MINIMUM, or nearer to it than to the X-axis MAXIMUM.

  • Page 122: Introduction

    Input Command Terminator Character Switches 13.6 13.5.3 Talk Only Switch 13.6 13.5.4 GPIB Switch Example 13.6 13.6 REMOTE/LOCAL Facility 13.7 13.6.1 Local Lock-Out 13.8 13.7 1250 Command Codes 13.9 13.7.1 Introduction 13.9 13.7.2 Command Code Format 13.9 13.7.3 Generator Commands 13.10 13.7.4 Synchroniser Commands 13.10...
  • Page 123 13.14.1 RS423 Port, Device Control Characters 13.27 13.14.2 Procedure for Storing a Learnt Program Externally, Via RS423 Port 13.28 13.14.3 Procedure of Loading a Learnt Program into the 1250, Via RS423 Port 13.28 13.14.4 Procedure of Loading a Learnt Program into the 1250, Via GPIB Port 13.28...
  • Page 124 Remote control of the 1250 can be achieved via either the General Purpose Interface Bus (GPIB) Interface, or the RS423 Serial Interface, both of which are fitted as standard. The 1250 can also be used in a system containing both GPIB and RS423 compatible devices.

  • Page 125: Connections

    1250 Frequency Response Analyzer 13.2 CONNECTIONS Connection to the GPIB is made via the 24-way connector on the rear panel of the 1250; see Fig. 13.2. The pin connections conform to the IEEE 488-1978 standard. Connection to the RS423 Serial Interface port is made via the 25-way sub-miniature D- type connector on the rear panel, see Fig.

  • Page 126: Gpib Switches

    The switches are read automatically on "power on" or when INITialise or BREAK is pressed. If the switches have to be altered after the 1250 has been set up, pressing BREAK will enable the new configuration to be read without disturbing any other data within the instrument, apart from the Serial Poll STATUS BYTE, as explained in Section 13.

  • Page 127: Address Switches

    13.5.3 TALK ONLY SWITCH The 1250 GPIB Interface is put into Talk Only mode when the Talk Only switch is in the down (ON) position. The Talk Only mode is used for GPIB plotting (described in Section 13.16) and outputting data to a GPIB printer (described in Section 13.12.2).

  • Page 128: Remote/Local Facility

    The 1250 offers two forms of control under the heading LOCAL: a. From the 1250 Front Panel and/or via the RS423 port. Both have equal priority. This mode is referred to as LOCAL 1.

  • Page 129: Local Lock-Out

    GPIB Controller. This facility can be used, for example, to prevent unauthorised Front Panel manipulations affecting the settings of the 1250. Fig. 13.4 shows the relationship of the LOCAL LOCK-OUT feature to the REMOTE and LOCAL states previously shown in Fig.

  • Page 130: Command Codes

    13.7 1250 COMMAND CODES 13.7.1 INTRODUCTION The Command language is based on the 1250 Front Panel operations. Each Command consists of a simple string of ASCII alpha-numeric characters whose significance parallels the hardkey-softkey arrangement. The numeric part of a Command can be in fixed point or floating point (exponential) format.

  • Page 131: Generator Commands

    2. Send ?TS0 to determine whether the overall test has been passed or failed. A number is returned: 0 =pass, 1 =fail. 3. If the Self Test has failed, determine which section of the 1250 has failed by sending successively ?TS1 (processor RAM), ?TS2 (processor ROM), etc., until a non-zero response is elicited, signifying a test failure.

  • Page 132: Amplitude Compression Commands

    1250 Frequency Response Analyzer The RS423 and GPIB Ports. Remote Control 13.7.5 AMPLITUDE COMPRESSION COMMANDS Facility Parameter Code Meaning Init Source 100=Ch 1 200=Ch 2 Value 1E-4 Error % error Limit 0=off, otherwise 10.23* Limit is on On/Off 0=off 1=on * 11.00V for 1250V...

  • Page 133: Sweep Commands

    The RS423 and GPIB Ports. Remote Control 1250 Frequency Response Analyzer Facility Parameter Code Meaning Init AUTO INTEGRATION TIME none none LAST RANGE USED numerator channel range denominator channel range STOP ANALYZERS none none SINGLE none none RECYCLE none none 13.7.8 SWEEP COMMANDS...

  • Page 134: Status Commands

    1250 Frequency Response Analyzer The RS423 and GPIB Ports. Remote Control PLOTTER Y-AXIS Y Item as X Item Y Maximum 1E18 -1E18 Y Minimum 1E18 -1E18 Y Origin 1E18 -1E18 PLOTTER Scale 0=fixed fixed SCALING 1=variable X-Minimum 32000 Y-Minimum 32000...

  • Page 135: Program Commands

    The RS423 and GPIB Ports. Remote Control 1250 Frequency Response Analyzer Facility Parameter Code Meaning Init LIST FILE none none CLEAR FILE none none FILE Number of File size none POPULATION results in file File pointer ~470 none NUMBER OF READINGS TAKEN...

  • Page 136: Function Commands

    1250 Frequency Response Analyzer The RS423 and GPIB Ports. Remote Control Facility Parameter Code Meaning Init GPIB OUTPUT 0=comma comma FORMAT SEPARATOR 1=terminator GPIB OUTPUT 0=crlf crlf FORMAT TERMINATOR 1=crlf + EOI 2=cr 3=cr + EOI RS423/GPIB 0=on REFORMAT ENABLE...

  • Page 137: Self Test Commands

    The RS423 and GPIB Ports. Remote Control 1250 Frequency Response Analyzer Facility Parameter Code Meaning Init BREAK none none LAST ERROR none returns error none number SET TIME I, I hours, none minutes none 13.7.19 SELF TEST COMMANDS Facility Parameter...
  • Page 138 1250 Frequency Response Analyzer The RS423 and GPIB Ports. Remote Control COMMANDS IN ALPHABETICAL ORDER (Continued) Code Meaning Step Variable Down. 1 = Slowest ------4 = Fastest Execute Program (n) Clear File Display File. 0= bof, 1 = eof, 2 = Step Down, 3 = Step Up, 4 = Summary FN 1 Angle Range.

  • Page 139: Commands In Alphabetical Order

    The RS423 and GPIB Ports. Remote Control 1250 Frequency Response Analyzer COMMANDS IN ALPHABETICAL ORDER (Continued) Code Meaning Meaning Heading Enable. 0 =on, 1 =off GPIB Output Format (1250N only, GPIB in Talker/Listener mode only) Reformat Enable. 0 = on, 1 = off Stop Analyzers Start/Continue Sweep.

  • Page 140: Gpib Controller: Language Used In Program Examples

    13.8 GPIB CONTROLLER: LANGUAGE USED IN PROGRAM EXAMPLES To clarify the use of the GPIB port for remote control of the 1250, several examples are given of GPIB Controller programs. Each example is written as a series of abbreviated commands, including some BASIC programming language instructions. The programs are representational only and are not suitable for directly programming a Controller.

  • Page 141: Measurement Output Selection

    Section 8. OUTPUT "?FR" INPUT A PRINT "FREQUENCY = ", A Note that the information sent from the 1250 to the Controller will include an Output Terminator, as explained in Section 13.12.6. 13.10 MEASUREMENT OUTPUT SELECTION: 13.10.1 VIA RS423 PORT...

  • Page 142: Measurement Output Rate

    This mode of presenting measurement results to the GPIB is selected by setting the TALK ONLY switch on the rear panel of the 1250 to ON. The 1250 then sends data to the GPIB ASCII port in a format suitable for GPIB-compatible printers. The format is the same as for the RS423 port, but the Output Terminator must be selected as described in Section 13.12.6.

  • Page 143: Gpib Normal Mode

    This mode of presenting measurement results is selected by setting the TALK ONLY switch on the rear panel of the 1250 to OFF. The data output is in compressed form, suitable for interpretation by a Controller. The 1250 automatically allocates to each parameter a constant field width of 11 characters, containing a 5-digit fixed point part and a 2-digit exponent.

  • Page 144: Dump Mode

    The RS423 and GPIB Ports. Remote Control 13.12.4 DUMP MODE This mode provides the fastest means of outputting data from the 1250. As the data is in binary form, however, it is suitable only for processing by a computer or for storage pending subsequent processing.

  • Page 145: Floating Point Format

    (carriage return). GPIB OUTPUT TERMINATORS AND SEPARATORS Output Terminators. When the 1250 sends a line of data to the GPIB, the line must be terminated by an Output Terminator character. The choice of character is determined by the requirements of the external device. The 1250 automatically generates crlf (carriage return line feed) as the default character, but others are available.

  • Page 146: Serial Poll/Parallel Poll

    Note that the status of all the bits, except "1" and "64", will continue to follow data changes, e.g. if the 1250 is on RECYCLE, bit 2 will be set to "1" as each Measurement is completed, then revert to "0" as a new Measurement commences.

  • Page 147: Parallel Poll

    = a number between 1 and 255, conforming to the bit numbers of the STB. For example SV8 will cause the 1250 to generate SRQ at the next End of Plot, and SV25 will generate SRQ from whichever event occurs first of "Error", "End of Plot" or "End of File”...

  • Page 148: Learnt Programs. External Storing And Reloading

    1250 at a later date. This greatly increases the number of programs that can he learnt, although the 1250 can still only hold up to 18 of them at a time; programs 1 to 9 in 'Normal' memory and programs 10 to 18 in 'supervisor' memory.

  • Page 149: Procedure For Storing A Learnt Program Externally, Via Rs423 Port

    2. Send the Command: from the external device. 3. The Program will be sent to the 1250 and stored under the Learnt Program number 4. The Program can now be executed from the Front Panel in the normal way, or via the RS423 port by sending the Command: 13.14.4 PROCEDURE FOR STORING A LEARNT PROGRAM EXTERNALLY,...

  • Page 150: Reloading A Learnt Program To 1250 Via Gpib

    13.14.7 RELOADING A LEARNT PROGRAM TO 1250 VIA GPIB Learnt Programs which have been saved or compiled on an external device can be reloaded to the 1250 by using the Learn Program Command *Ln, as shown in the following example for loading Program 1.

  • Page 151: File Output

    1. Ensure that the 1250 is in LOCAL 1 or LOCAL 2 mode. 2. Set up the relevant external device, connected to the RS423 port. 3. Instruct the 1250 to switch the RS423 section of the DATA OUTPUT switch to "all" by sending the Command: OP 1,1 from the external device.

  • Page 152: Example Of Controller Program For Copying The File To The Gpib Without Handshake

    If the GPIB plotter can be put into Listen Only mode, it can be driven directly from the 1250 without requiring a Controller. However, if the plotter has no Listen Only mode, a Controller is necessary to instruct the plotter to "listen" to the 1250. When directly driving a plotter possessing Listen Only facility, the 1250 must have the switch on its rear panel set to TALK ONLY.

  • Page 153: Operating Sequence For Gpib Plotter, Using Acontroller

    13.16.1 OPERATING SEQUENCE FOR GPIB PLOTTER, USING A CONTROLLER To perform a GPIB plot using a Controller, first set up the 1250 for the desired type of sweep and set the plotter controls. This preliminary setting up can either be performed using the Front Panel keys, as described in previous Chapters, or remotely from the Controller using the Commands given in Section 13.7 of this Chapter.

  • Page 154: Chapter 14 Break, Self Test, Time Display And Power Fail

    Break, Self Test, Time Display and Power Fail 1250 Frequency Response Analyzer Break, Self Test, Time Display and Power Fail Section Page 14.1 The Break Key 14.2 2 Self Test 14.2 14.3 Time Display 14.4 4 Power Fail 14.5 14-1...

  • Page 155: The Break Key

    1250 Frequency Response Analyzer 14.1 THE BREAK KEY Note that this key operates only when the 1250 is in the Local mode. When pressed, it instantly stops any activity upon which the 1250 is engaged, and the message BREAK IN is displayed. Its main functions are: 1 .
  • Page 156 If a fault is detected, the Display will show a message indicating the faulty area, e.g.: Figure 14.3 - Check Fail Display In this case, the 1250 should be switched off until the fault can be rectified. It is unlikely that the instrument will be damaged if left switched on, but the readings are suspect.

  • Page 157: Time Display

    If a fault is detected, the Display will show a message indicating the faulty area, e.g.: Figure 14.3 - Test Fail Display The 1250 should be switched off until the fault can be rectified. It is unlikely that the instrument will be damaged if left switched on, but the readings are suspect.

  • Page 158: Power Fail

    14.6: Fig. 14.6 - Power Restored Display This signifies that the 1250 has correctly remembered all the menu settings from the last time it was used. Therefore, after the Generator, Analyzers, etc. have been restarted, the instrument may continue to be used as if it had not been switched off.
  • Page 159 Options Section Page 15.1 Synchroniser Unit 12501 15.2 15.1.1 Introduction 15.2 15.1.2 Description 15.2 15.1.3 Installation 15.2 15.1.4 Connecting Up 15.2 15.1.5 Modes of Operation 15.3 15.1.6 The Synchroniser Menu 15.5 15.1.7 Procedure for Establishing the Sync. Locked State 15.8 15.1.8 Synchroniser Status 15.9...

  • Page 160: Synchroniser Unit 12501

    A length of ribbon cable with DIL plugs at each end. 15.1.3 INSTALLATION A 12501 ordered with a new 1250 will be installed and tested at the factory. When the 12501 is to be added to an existing 1250, installation must be performed by a Solartron engineer.

  • Page 161: Modes Of Operation

    15.1.5 MODES OF OPERATION There are four modes of synchroniser operation: Off. In this mode, the 1250 behaves as though the 12501 is not present. Synchroniser parameters can be entered but the measurements are unaffected by them. The "off' state is selected via the SYNC soft key described in Section 1.6 Loose Lock.
  • Page 162 Fig. 15.1 - Use of RATIO Mode for Indirect Synchronising When the decimal value of the gear ratio is entered into the 1250, the instrument computes the rotational frequency of the main shaft, and synchronises the measurements to this frequency rather than that of the secondary shaft.

  • Page 163: The Synchroniser Menu

    Fig. 15.3 below. Enter a voltage value between the limits ±5.1V. If no value is entered after Initialisation, the 1250 will use the default value of zero. i.e. synchronise to the zero-crossing point of the waveform.
  • Page 164 Options 1250 Frequency Response Analyzer COUPLING. May be DC or AC, the former being the default state. AC coupling should not be used at low frequencies, as defined in the Specification, Chapter 17. SLOPE. Maybe +ve or -ve, as illustrated in Fig. 15.3 below. Select and enter the slope which produces the best defined trigger.
  • Page 165 Analyzers. If numbers are entered for both Ratio and Harmonic, the 1250 will use the product of the numbers: e.g. enter 3 in Ratio and 3 in Harmonic, and the 1250 will measure the response at the 9th Harmonic.

  • Page 166: Procedure For Establishing The Sync. Locked State

    Options 1250 Frequency Response Analyzer 15.1.7 PROCEDURE FOR ESTABLISHING THE SYNC. LOCKED STATE 1. Initialise. 2. Ensure that the input trigger signal is connected to the 12501. 3. Select "SYNC" in the Mini Status Display. The state indicated may be IDLE, WAIT...

  • Page 167: Synchroniser Status

    At least two frequency readings have been taken and compared, and the times between consecutive pairs of trigger pulses have been found to be identical; i.e. the input frequency is stable. LOCKED Lock has been achieved, and the 1250's Analyzers will now measure at the correct frequency. FAULT The Synchroniser cannot achieve, or retain, the LOCKED stated.
  • Page 168 Page 1 of the Status information can be interrogated externally by sending the Code "?SN". The 1250 will reply with a number. as shown in Chapter 13, Section 7.4. The meanings assigned to the numbers are as defined for the messages in the Display. The additional message "0", i.e.

  • Page 169: Measuring Harmonics: Use Of Order Analysis

    The measurements obtained using Order Analysis benefit from the following advantages, compared to the Ratio mode/Harmonic Analysis method: a) Results are far more accurate because the 1250-works in phase locked mode. Hence, even long integration times may be selected to give accurate results.

  • Page 170: Modulator/Demodulator Unit 12502

    Self Test (see Chapter 14, Section 2 "Self Test"). 15.2.2 INSTALLATION A 12502 ordered with a new 1250 will be installed and tested at the factory. When the 12502 is to be added to an existing 1250, installation and calibration must be carried out by a Solartron engineer.

  • Page 171: Analog Plotter Interface 12503

    Chapter 12, Section 4 "X-Y Plotter". It is necessary that the 1250 has at least Issue 03 software; this may be determined by using Self Test (See Chapter 14, Section 2).

  • Page 172: Preset Controls

    Options 1250 Frequency Response Analyzer 15.3.3 PRESET CONTROLS 12503 carries two sets of 4 switches, close to the top edge, which may be accessed when the board is in the frame. The 'on' and 'off' positions of the switches are as shown: Fig.

  • Page 173: Introduction

    15.4.3 INSTALLATION A 12506 ordered with a new 1250 will be installed and tested at the factory. When the 12506 is to be added to an existing 1250, it is recommended that installation be performed by a Solartron engineer.

  • Page 174: Setting Up

    Options 1250 Frequency Response Analyzer 15.4.4 SETTING UP As the frequency of the 12506 is synchronised to the main Generator, there are only three soft keys to set, viz: AMPLITUDE, BIAS and WAVEFORM. These keys operate in a similar manner to the main Generator keys described in Chapter 4. There is no separate modulation facility;...
  • Page 175 1250 Series Options 16.2 16.4 Connecting Up 16.4 16.4.1 Safety: Connecting the ac Mains 16.4 16.4.2 Connecting up the 1250-1251 Interface Bus 16.4 16.5 1251 Unit Identification Switches 16.5 16.5.1 Analyzer Channel Numbering 16.5 16.6 Manual Operation of the System 16.5...

  • Page 176: Introduction

    The 1251 Units and the host 1250 are interconnected via the 1250-1251 Interface Bus as shown in Fig. 16.1. This bus is used to route all control commands from the 1250 to the 1251 Units; it can also route measured data from each 1251 Unit back to the 1250 for display or other processing or for onward transmission to the IEEE 488 Interface Bus via the IEEE 488 port of the 1250.
  • Page 177 1250 Frequency Response Analyzer The 1251 Multichannel Analyzer System Fig. 16.1 - 1250/1251 Multichannel System Configuration 16-3 AMK/1250/1...

  • Page 178: Connecting Up

    16.4 CONNECTING UP 16.4.1 SAFETY: CONNECTING THE AC MAINS The safety precautions and connecting procedures given in Chapter 2 for the 1250 FRA apply equally to each of the 1251 Units. Note: Setting the Unit Identification Switches. Before the system is switched on, the Unit Identification switches on the rear panel of each 1251 Unit in the system must be correctly set.

  • Page 179: 1251 Unit Identification Switches

    1250 as described below. Alternatively, the system operation may be commanded through a remote Controller connected to the IEEE 488 or RS 423 interface port of the 1250, as described in Section 16.7. To operate the 1251 System manually the Analyzer and Display/Plotter menus must be set up specifically for multichannel use, in addition to the setting up of the 1250 for conventional two-channel use.

  • Page 180: Setting Up The 1251 Analyzers

    2. To check that all the 1251 Units present have been recognised correctly, press the STATUS key on the 1250, and then the ANALYZER soft key. Use the SELECT key to step through the pages of Analyzer status information; only correctly recognised channel numbers will be displayed, and appear in the order Ch1, Ch2, Ch11 to Ch18, Ch21 to Ch28, Ch31 to Ch38, Ch41 to Ch48.

  • Page 181: Remote Operation Of The System

    16.7.1 INTRODUCTION The command structure for operating the 1251 Multichannel Analyzer System using an external Controller is identical to that used for 1250 remote operation. Details of the remote operating commands are given in Chapter 13. This section covers features peculiar to the remote operation of the 1251 System.

  • Page 182: Setting Up The Gpib Configure Menu

    The operation of reading data from the GPIB output buffer is also different in the 1251 compared to the 1250 Unit. In the 1250, once data has been read from the GPIB output buffer, it is not possible to access the buffer again until new data is available. This allows the Controller to wait for new data by holding on a READ statement.

  • Page 183: Gpib Addresses

    GPIB addresses. However, whilst the GPIB address of the 1250 can be either of two values (the Major and Minor addresses) depending on the output mode adopted, a 1251 Unit has only one address whether operating in ASCII or DUMP Output (binary) mode.

  • Page 184: Dump Mode Format

    Output Terminator has been selected (Chapter 12, Section 1). Appropriate Output Terminators are either cr+EOI, or crlf+EOI, chosen during the setting up of the 1250 GPIB CONFIGURE Menu (Section 7.3).

  • Page 185: 1251 Multichannel Analyzer Specification

    Slave analyzer system, operating in RESULTS conjunction with 1250 Frequency Response Specification as for 1250 FRA except as Analyzer. Up to four 1251 units may be shown below. Single point from any 1251 used with each FRA, with each 1251...
  • Page 186 Specification...
  • Page 187 Coupling: dc or ac (<1dB at 2.5Hz) Impedance: Hi or Lo to ground: 1MΩ,<100pF 1250 converts from one co-ordinate form to another (front+rear sockets) with negligible arithmetic error. Common mode rejection, dc coupling, up to 100Hz: up to 50V peak: >65dB...
  • Page 188 1250 Frequency Response Analyzer Specification PLOTTING Generator output General May modulate either Carrier 1 or Carrier 2. Data source: single channel or point-to-point Carrier phase shift, 50Hz to 300Hz: <3° Parameters, X or Y axis: a, b or r 300Hz to 3kHz: <1°...
  • Page 189 Index Subject Page 1250 Command Codes..............13.8 1250 Series Option..............1.8, 16.2 1250-1251 Interface bus..............16.2 1250 Variants.................. 1251 ASCII Format................. 16.9 1251 Analyzer, Setting up............... 16.6 1251 Connecting up................ 16.4 1251 Data Transfer Speeds............16.8 1251 Dump Mode Format...............
  • Page 190 Changing Menus during Recycle............Channel and Range Column Conventions........... 12.6 Clear Key.................... Co-ordinates..................Command Code Format..............13.9 Command Query ..............13.19 Commands in Alphabetical Order............13.16 Commands, Miscellaneous..............13.15 Controller Program for Copying the File to the GPIB......13.31 Controller Program for Transferring Learnt Program......13.29 Copying a Program................
  • Page 191 File Output via GPIB Port..............13.30 File Output via RS423 Port by External Command......13.30 File, Overwriting Results in.............. 12.7 File, Starting..................12.8 File, Use of ..................Fitting Telescopic Slides: Mounting Kit 12505B (Accuride)........... Mounting Kit 12505C (Jonathan)..........2.11 Floating Point Format............... 13.23 Frequency..................
  • Page 192 Keyswitch..................Keyboard..................Learnt Programs: External Storing and Reloading............. 13.27 Limits....................10.6 Linear Sweep..................Loading a Learnt Program: via RS423 Port................13.28 via GPIB Port................13.28 Local Lock-Out.................. 13.7 Logarithmic Sweep................Logarithmic or Linear Sweep, Setting Up........... Looping and Calling................12.13 Mains Connecting................
  • Page 193 RS423 and GPIB Devices, combinations..........13.32 RS423/GPIB Commands..............13.14 Rack Dimensions................. Rack Mounting..................Range....................Reformat..................... 12.4 Reloading a Learnt Program to 1250 via GPIB........13.29 Resetting..................... Safety Precautions: Installation............Scaling....................10.5 Self Test....................14.2 Self Test Commands................13.16 Serial Poll.................... 12.6 Serial Poll/Parallel Poll................
  • Page 194 Sweep Idle or Hold Status, Commands Producing....... Sweep Stop Status, Commands Producing.......... Sweep Termination Conditions............Sweep Time, Automatic............... Sweep, Stopping and Re-starting............Sweep: Changing Parameters in Mid Sweep........Switch on..................... Sync, Locked State, Establishing............15.8 Synchroniser Commands..............13.10 Synchroniser Menu................15.5 Synchroniser Status................

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