Page 1 C Updating which contains manual changes for later instruments. Be sure to examine this supplement for changes which apply to your instrument, and record these changes in the manual. HP Part No. 08 112-90004 Microfiche Part No. 08112-95004 Printed in Federal Republic of Germany...
Page 2 Notice Subject Matter Notice The information in this document is subject to change without notice. Hewlett-Packard makes no warranty of any kind with regard to this printed material, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Hewlett-Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance or use of this material.
Page 3 Printing History New editions are complete revisions of the manual. Update packages, which are issued between editions, contain additional and replacement pages to be merged into the manual by the customer. The date on the title page and back cover of the manual only changes when a new edition is published.
Page 4 This Hewlett-Packard instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment. During the warranty period, HP will, at its option, either repair or replace products which prove to be defective.
Page 5 Exclusive Remedies The remedies provided herein are the Buyer’s sole and exclusive remedies. HP shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether based on contract, tort, or any other legal theory. Assistance Product maintenance agreements and other customer assistance agreements are available for Hewlett-Packard products.For any...
Page 7: Table Of Contents
... . . Instrument Description HP 8112A Options ....... . . Accessories Recommended Test Equipment .
Page 8 Connector ....HP-IB HP-IB Logic Levels ....Operating Environment ... . .
Page 9 Rear Panel 4-18 Connector ....HP-IB 4-18 ....
Page 10 Error, Fault and Status Reporting 6-13 HP-IB Status Byte ....Limit Error (Bit 0) ....
Page 11 Buffer not Empty (Bit 7) 6-18 HP-IB Universal Commands .......
Page 12 7-16 Learn String (Double Mode active) ..7-18 INTERROG ....7-18 Purpose ....7-18 Comments .
Page 13 ....Procedure HP-IB Verification Test ... . . Test Setup ....
Page 14 10.1-l Trouble shooting ....10.1-3 Preparing the HP 8112A for servicing ..10.1-3 Key Jammed ....
Page 15 10.1-5 El2 ....10.1-5 El3 ....10.1-5 El4 .
Page 16 10.3-4 TIME Mode ....outputs ....10.3-5 10.3-5 Error Output .
Page 17 ..10.7-2 Microprocessor Interface Signals 10.7-3 HP-IB Interface Signals ... 10.7-4 ....Address Decoding .
Page 18 Display Driver U22 ... . . 10.7-6 ..HP-IB Status Latch U37 10.7-6 Display Latche U23 ... . .
Page 19 3-3. HB-IB Connector ......4-l. HP 8112A Front Panel ... .
Page 20 8-29 8-21. Correct Delay Control ... . . 8-22. HP-IB Verification Test ... . 8-30 9-l. Access to the HP 8112A for Adjustments .
Page 21 ....B-10. Rear Panel B-39 B-11. HP-IB Address Switch (Factory setting) ..B-40 ..B-42 B-12.
Page 22 8-l. Test Equipment ....9-l. Adjustment Procedures - Changeable Components 10-4 10-l. HP 8112A Board Assemblies & Servicing Chapters 10.2-2 10.2-l. Power supply rectifiers ... .
Page 23 ..A-l. HP 8112A Parts Manufacturers ..A-2. Standard HP 8112A Master Parts List ... . A-3. Main Board Parts List A-26 .
Page 25: Introduction
Introduction General This manual describes the following procedures for the HP 8112A 50 MHz Programmable Pulse Generator: Installation Programming Testing Performance Adjustment Servicing A Microfiche version of this manual is available on 4x6 inch microfilm transparencies (refer to title page for order number).
Page 26: Instrument Description
The self-prompting operation and HP-IB programmability of the HP 8112A ensure that it is quick and easy to use in stand-alone and automatic-test applications. Self-test and fault diagnosis are performed each time the instrument is switched on. Error recognition (and prompt) helps the operator to recover from incorrect front panel or programming operation.
Page 27: Accessories
Accessories Included The HP 8112A is supplied complete with the following: HP Part Number Item 750 mA fuse for 2201240 V operation 21 lo-0813 1.5 A fuse for 100/120 V operation 2110-0043 Power cable See Chanter 3 installation Available The following accessories are available for the HP 8112A:...
Page 28: Recommended Test Equipment
The recommended test equipment and accessories required to Recommended Test maintain the HP 8112A. are listed in Table l-l. Alternative Equipment equipment may be substituted, provided that it meets or exceeds the critical specifications given in the tables. Table l-l. Recommended Test Equipment...
Page 29: Specifications Introduction
Specifications Introduction All specifications in the following sections describe the warranted performance of the instrument: Timing parameters Output parameters Waveform characteristics All specifications apply with a 50 52 load, after a 30 minute warm-up period, and are valid for ambient temperature in the range 15OC to 35°C.
Page 30: Period (Per)
Period (PER) Range 20.0 ns to 950 ms Delay (DEL) (after Range Trigger Out) 75.0 ns to 950 ms (max:PER+55 Accuracy Double Pulse (DBL) (interval between Range leading edges) ns to 950 ms (max:PER-WID) DEL and DBL are mutually exclusive Pulse Width (WID) Range Duty Cycle (DTY)
Page 31: Output Parameters
Output Parameters Note Output voltages are specified for a 50 R load. Output voltages double when driving a high impedance load. -7.90 v to t43.00 v High Level (HIL) Low Level (LOL) -8.00 V to i-7.90 V Resolution 3 digits (10 mV) Level accuracy Repeatability factor 4 better than accuracy...
Page 32: Trigger Modes
Trigger Modes The external trigger signal referred to in this section is applied to the EXT INPUT BNC connector on the instrument front panel. The trigger level and sense are adjustable. An external trigger can be simulated by pressing the LMAN) key. The [-PULSE) key gives an additional pulse in Gate and External Burst modes.
Page 33: Output Modes
Output Modes Complement Selectable on/off Disable Disconnects output, default at switching on. Limit Implements present output levels as output limits. Fixed transitions 5 ns from 10% and 90% amplitude, 3.5 ns from 20% to 80% amplitude Cosine transitions Up to 25% faster between 10% and 90% of amplitude than linear transitions Linear transitions Inputs and Outputs...
Page 34: Main Output
Visual and Status Byte indication of incompatible settings, under-range control voltage, and clipped amplitude (excessive transition time). HP-IB Capability The HP 8112A is fully programmable except for the External Input trigger level. Capability codes Learn modes All or individual parameters can be programmmed and uploaded...
Page 35: General Characteristics
Status byte Returns text of operating-error message Message Times Time to receive and execute a message 5 ms (Offset 30 ms) Time to send a message Status byte 15 ms Learn string 1 ms per character, Status byte:15 ms General Characteristics Environmental Storage temperature range...
Page 37: Installation Introduction
Safety The HP 8112A is a Safety Class 1 instrument (instrument with an exposed metal chassis that is directly connected to earth via the Considerations power supply cable).
Page 38: Power Requirements And Line Voltage Selection
Power Requirements ! and Line Voltage Selection BEFORE APPLYING AC LINE POWER TO THE HP 8112A, Caution ensure that the instrument is set to the local line voltage and the correct line fuse is installed in the fuse holder. The instrument requires a power source of 100, 120, 220 or 240 V rms (-l-5%, -10%) at a frequency of 48-440 Hz single phase.
Page 39: Power Cable
Intentional interruption of the protective ground connection is prohibited. In accordance with international safety standards, the HP 8112A is equipped with a three-wire power cable. When connected to an appropriate ac power receptacle, this cable grounds the instrument cabinet.
Page 40 The following work should be carried out by a qualified electrician - all local electrical codes being strictly observed. If the plug on the cable does not fit the power outlet, or the cable is to be attached to a terminal block, cut the cable at the plug end and re-wire it.
Page 41: Hp-Ib Connector
HP part number 1251-0293. HP-IB Logic Levels The HP 8112A HP-IB lines use standard TTL logic, the levels being as follows: True = Low = digital ground or 0 Vdc to 0.4 Vdc, False = High = open or 2.5 Vdc to 5 Vdc.
Page 42: Operating Environment
Environment Warning The HP 8 112A is not designed for outdoor use. To prevent potential fire or shock hazard, do not expose the HP 8112A to rain or other excessive moisture. Temperature The HP 8112A may be operated in temperatures from 0°C to 55°C.
Page 43: Storage And Shipment
If the instrument is to be shipped to a Hewlett-Packard Sales/Service Office, attach a tag showing owner, return address, model number to HP and full serial number and the type of service required. The original shipping carton and packing material may be re-usable,...
Page 45: Operating
3. Ensure that the device under test cannot be overdriven by the HP 8112A output (16 V p-p into 50 R; 32 V p-p into high impedance). 4. Ensure that the maximum external voltage a,pplied to the HP 8112A falls within these limits: -5 V to t5 V dc).
Page 46 Figure 4-1. HP 8112A Front Panel Switching On The HP 8112A performs a “self test” when the power is switched on. All the front panel LEDs should light momentarily. If a fault is detected, the word “ERROR” is illuminated and an error code is displayed on the front panel digital display.
Page 47: Error Codes
Fail Output Amp +ve Offset test Fail Output Amp -ve Offset test E31 to E39 Fail Overall tests The output amplifier is faulty. Fail Burst Counter tests Refer to Chapter 10.1 for more information on the error codes and their causes. When the self-test is completed successfully, the instrument automatically assumes the operating state which was active when it was last switched off, except that the output is disabled to...
Page 48: Standard Parameter Set
Standard Parameter The Standard Parameter Set exists for two reasons: If the instrument RAM becomes corrupted due to battery failure, the Standard Parameter Set will be selected when the instrument is switched on to give an error free display. If an invalid combination of Operating and Control modes is selected, switching the instrument off and on again, or selecting RCL 0, will revert to the Standard Parameter Set.
Page 49: Selecting Trigger Mode
Selecting Trigger Mode 8112A PULSE GENERATOR 50MHz 0 TRIG Figure 4-2. Trigger Mode Controls Mode Selection The currently active mode is shown by LED indicator. The trigger mode can be cycled through available options by pressing the key below the mode indicators.
Page 50: Controlling The External Trigger
Controlling the External Trigger 8112A PULSE GENERATOR 50MHz Figure 4-3. External Trigger Controls The external trigger signal required in some trigger modes must be EXT INPUT applied to the BNC connector. Caution Do not apply voltages outside the range f20 V to the EXT INPUT connector.
Page 51: Selecting Control Mode
An analog signal can be applied to the control .input to modulate or Control Input control the HP 8112A output signal. This external input may be any waveform in the range f20 V. However, the overall range within which the instrument actually responds to a control signal, is 1.0 V to 10 V, as shown below.
Page 52: Mode Selection
Depending on the control mode selected, the output signal may be Mode Selection either Period, Delay, Width, or High Level controlled, by an external voltage applied to the CTRL INPUT. The control mode can be cycled through available options by pressing the key below the mode indicators and the currently active mode is shown by an LED indicator.
Page 53: High Level Control Capabilities
becomes non-operational in this Control mode, and the button LED will blink. See Figure 4-6. Maximum LOL set (+7.95V)+ - 8 ” 4 CTRL Input The dotted line shows the HII-C range Figure 4-6. High Level Control Capabilities Operating 4-9...
Page 54: Setting Transition Modes
LEE or TRE parameters when this key is operated (lit). Linear I/l Permits both the leading and trailing edges of the HP 8112A output pulse to be programmed independently of each other, in the range 6.5 ns to 95 ms, by setting values for LEE and TRE. Maximum permissible ratio is 1:20.
Page 55: Up And Down-Ranging, Using The Vernier Keys
There are seven overlapping ranges for linear and gauss transitions, Transition Ranges and it is important to note the following: Within any range, the maximum ratio of the leading edge transition time to the trailing edge transition time is 1:20 and vice versa.
Page 56: Up And Down-Ranging Using The Range Key
X = Non-active Slope Y = Active Slope Figure 4-9. Ranging examples Table 4-2. Active slope moves from Range 3 to Range 2 (Yl) Inactive slope Change Value Reason in overlap with higher range (4) Table 4-3. Active slope moves from Range 3 to Range 4 (Y2) no change in overlap with higher range When this key is used to move a currently active slope up or down...
Page 57: Setting Parameters
Setting Parameters 8112A PULSE GENERATOR 50MHz - V E R N I E R O V I D o L B q q q q q pJ q us 1 0 “RCL Figure 4-10. Parameter controls The parameters available for selection depend on the currently selected modes.
Page 58: Per
High and Low level set. Keys PHIL) @iJ The selected HIL value is inoperative in the HILC mode. Note This key causes the HP 8112A to assume a factory programmed Set Key m parameter set as follows: NORM Active Active...
Page 59: Store And Recall Key (M)
Store and Recall Key The HP 8112A has the capability to store nine complete sets of mode and parameter information in it’s memory. To store settings, press (KQiEj. The digital display now reads vernier key is used to alter the value of X, to determine which file the parameter set will be stored as.
Page 60: Selecting Output Mode
Selecting Output Mode Figure 4-l 1. Output controls Limited Output Pressing the (LIMIT] key sets the current high and low output levels (HIL,LOL) as output limits which cannot be exceeded until limited output mode is switched off. While limited output mode is active, the high and low output levels (HIL,LOL) can be varied within the output limits.
Page 61 Do not apply an external voltage greater than f5 V, or electrostatic Caution discharge to the output connector. Operating 4-17...
Page 62: Rear Panel
Figure 4-12. Rear panel HP-IB Connector Refer to Figure 3-3 for a definition of the HP-IB connector pins. Refer to “Setting the HP-IB Address” in Chapter 6 if you want to know how to set the instrument’s HP-IB address. x-out Not used with HP 8112A.
Page 63: Operating Examples
Operating Examples Introduction To obtain an output from the HP 8112A it is only necessary to set the mode, period and transition type. Then press the green m key. A stable error free pulse train is generated and you can then alter parameter values, and external input and control modes to derive your desired output.
Page 64: Trig Mode
4. Select each output parameter in turn by pressing its associated key. Adjust the parameter value using the (m’ and (RANGE] keys. Refer to Chapter 4 Operuting for additional information on parameter adjustment. 5. If a Control Function is required, select the required mode by repeatedly pressing the control mode key until the required mode is lit.
Page 65: Gate Mode
6. Select each output parameter in turn by pressing its associated key. Adjust the parameter value using the (VERNIER) and cm] Operating keys. Refer to Chapter 4 for add:itional information on parameter adjustment. 7. If a Control Function is required, select the required mode by repeatedly pressing the control mode key until the required mode is lit.
Page 66: External Width Mode
6. If a Control Function is required, select the required mode by repeatedly pressing the control mode key until the required mode is lit. Apply the Control signal to the CTRL INPUT connector. Refer to Chapter 4 Operating for more permissible combinations of Operating and Control modes.
Page 67: External Burst Mode
Note You may wish to set up Output Limits as described in Chapter 4 Opemting to protect the device under test. 7. Press the CDISABLEI) key to turn off output disable mode and enable the output (LED extinguished). External Burst Mode I N PUT M A I N OUTPUT...
Page 68: Applications
Applications Analog Applications Fixed transition mode The fixed transition time (5 ns), is ideally suited for step response measurements such as: ringing, settling time). Reverse recovery time of transistors and diodes. inductance, high frequence capacitance). Figure 5-6. Capacitance circuit Linear transition mode Independantly variable leading and trailing edges between 6.5 ns and 95 ms can be used to generate ramps or sawtooth waveforms for: Stimulation of hydraulic or pneumatic devices...
Page 69: Digital Applications
over telephone lines Digital Applications Fixed transition mode Can be used for stimulation of fast logic components and circuits as follows: Clock generation Producing known good data inputs for logic sub assemblies and modules maximum clock speed noise sensitivity and threshold level verification 0 set-up time hold time propagation delay...
Page 71: Programming
ANSI Interface Standard MC1.l. HP Publication 5952-0058 HP Publication 5952-0156 Setting the HP-IB The HP 8112A’s HP-IB address is set at the factory to 12 decimal. The address is stored in the instrument’s RAM, along with the Address current instrument settings.
Page 72: Local, Remote And Local Lockout
The output signal and all instrument settings remain unchanged following a change from local to remote mode. Local Lockout The a key can be disabled by sending an HP-IB Local Lockout command from the system controller (use the LOCAL LOCKOUT statement in BASIC 5.0/5.1).
Page 73: Abbreviations Used In This Document
The HP 8112A accepts the following terminators: LF and EOI Note LF alone is not accepted as terminator when the HP 8112A is connected to a HP9000 Series 200/300 controller. When connected to other controllers, the HP 8112A may accept LF as terminator.
Page 74: Programming
Example: To set the Period to 2.2 ms, the ASCII mnemonic PER followed by the new value 2.2 and the unit MS must be sent to the HP 8112A. HP Basic Statement for this is: OUTPUT 712;"PER 2.2 MS"...
Page 75 The HP 8112A can be programmed into an error condition in just the same way as when using the front panel. For example, attempting to program a larger LOL than HIL: OUTPUT 712;"HIL 1 V,LOL 2 V" Refer to “Error, Fault and Status Reporting” for details of error, fault and status reporting using the HP-IB.
Page 76: Selecting Trigger Modes
Selecting Trigger Modes Standard Trigger Modes Mnemonic Action Select NORM Select TRIG Select GATE M3 Select E.WID M4 Select E.BUR M5 Trigger Control Mnemonic Action Select trigger off Select positive trigger slope Select negative trigger slope Select both OUTPUT 712;“M3,Tl” Example Select GATE mode with a positive trigger slope.
Page 77: Selecting Output Waveform Mode
Selecting Output Waveform Mode I Mnemonic Action Select fixed Select linear S e l e c t gaussian W3 Select mode off S M O Select mode on OUTPUT 712; “W2 ,SMl” linear output waveform transitions Example Select Setting Parapeters A parameter programming mnemonic is the sa.me as its front panel Note DEL = delay for example.
Page 78: Level Parameters
Level parameters plus 2 V, Example OUTPUT 712;“HIL 2 V,LOL -1.25 V” Set high level to low level to minus 1.25 V Burst Parameter Action Mnemonic Value Delimiter Set burst number Provides a burst of 375 output pulses Example OUTPUT 712; “BUR Vernier Action Mnemonic...
Page 79: Range Change
Range Change Change vernier range upwards OUTPUT 712. “Flu” Example Stored Parameters Value Delimiter 1 ..9 Set ident 0 = Standard 1 ..9 Stored set Store current parameters set instrument OUTPUT 712; Example as setting number :i Revert instrument to standard parameter...
Page 80: Reading Parameters
Function Commands. After Sending a Talker Function Command the HP 8112A will return a response message. A response message remains in the HP 8112A output queue until it is read or another command is issued. For example, to read the current value of the Period, the following...
Page 81: Selecting Output Modes
Programming Examples contains more details about the usage of the CST command. Also refer to the example program INTERROG. When the HP 8112A replies with a string containing all current settings. The data is always in the same order: 200 US,DEL 65.0 NS, 001 #,PER 1.00 MS,DBL...
Page 82: Example
Read reply into allocated ENTER 712;B$ m e m o r y Print the reply. PRINT The time taken for the HP 8112A to receive and implement a Timing programming message can be divided into three parts: Data Transmission Time Send This is the time taken to transmit the programming message over the HP-IB, which is 130 11s ms per ASCII character (7.6 kByte/sec).
Page 83: Hardware Settling Time
For example, bit 0 represents all types of Limit errors. (See the operating manual of the HP 8112A) 13it 6 of the STB is the Request Service (RQS) Bit and is set whenever a service request is caused.
Page 84: Limit Error (Bit 0)
(Bit 0) status byte. The conditions which cause them and the description used by the HP 8112A when replying to an IERR command are listed below. The limit error bit is not latched, therefore a transient error is only recorded by generating an SRQ.
Page 85: Timing Error (Bit 1)
There are two types of error (shown for NORM mode only) which set the timing error bit in the status byte. The conditions which cause (Bit 1) them and the description used by the HP 8112A when replying to an therefore a transient error is only recorded by generating an SRQ. Note More than one error condition can occur at one time.
Page 86: Example
30 ms may be achieved. Note In the permanently stored Mode/Parameter settings in the HP 8112A ROMs, “SR” is set to “0” (zero). If these settings are recalled as current settings, the Service Request function can be re-activated by programming “SR” to “1”.
Page 87: Input Error (Bit 5)
(Bit 6) Buffer not Empty This bit is set when there is data in the HP 8112A input buffer. can monitor this bit to determine if the instrument has finished (Bit 7) interpreting a lone: nroerammine: message.
Page 88: Hp-Ib Universal Commands
My talk address selectable An HP-IB DCL command causes the HP 8112A to load its standard parameter set. The instrument remains in its current mode (local or remote). An HP-IB SDC command causes the HP 8112A to load its standard parameter set and enter remote mode.
Page 89: Hints For Solving Problems That Might Occur
The hardware settling time must also be consklered. (See Chapter 2 Specifications for more details). When a command is sent to the HP 8112A, the device places all received characters into a buffer. Interpretation of the command(s) starts as soon as a valid terminator is received.
Page 90: Terminators
Transfer jumper A3W3 at the center of the microprocessor board A3 from the factory setting EOI to position 3. The HP 8112A (with old and new firmware) does not pull the EOI line. The device terminates all messages with CR/LF and a space character.
Page 91: Interrogate Timing
The HP 8112A needs time to interpret and implement the commands which it receives. You need to allow for this in your controller program. A summary of programming timings is given in Table 6-l.
Page 93: Programming Examples
Demonstrates the usage of all types of interrogate commands offered by the HP 8112A Note In the examples it is not strictly necessary to put the HP 8112A into remote mode using the REMOTE 712 command because: The CLEAR 712 statement used to initialisle the instrument also selects remote mode.
Page 94: Testing Communication
100 ms. Programming applications should include an initial check that the HP 8112A is communicating correctly. A suitable quick check is to set a parameter to a particular value and then read it back, as illustrated by the flow chart and program example given here.
Page 95 (RMT and ADS LED's on, DEL key LED on, 'I.00 ms' displayed) "Interrogate Delay" command OUTPUT Adr;"IDEL" ENTER Adr;A$ Input data from HP 8112A Print on screen PRINT A$ (Printout Return HP 8112A to local operating mode LOCAL Adr Programming Examples 7-3...
Page 96: Performing Self-Test
C O N T I N U E The HP 8112A RAM/Hardware self-test can be initiated via the HP-IB using the EST message. If a fault is detected, the HP 8112A sets the System Failure and Service Request bits in its HP-IB Status Byte.
Page 97 LED on> OUTPUT Adr;"EST" (RMT and ADS LED's on> WAIT 1000 IF A=#0 THEN !If Status Byte is zero, HP 8112A has a fault PRINT "HP 8112A FAULT WITH ERROR";A-64 END IF LOCAL Adr HP 8112A Self-test Programming Examples 7-5...
Page 98: Using The Buffer Not Empty Flag
Y E S C O N T I N U E The Buffer Not Empty flag indicates that the HP 8112A is currently interpreting a programming message. You can use the flag to make the system controller wait until a message has been implemented before proceeding.
Page 99 Comments: interface, set HP 8112A to CLEAR Adr CLEAR SCREEN OUTPUT Adr;"M2,Tl,W2,PEFl !and change period, delay and width REPEAT UNTIL BIT(A,II)=O LOCAL Adr Programming Examples 7-7...
Page 100: Common Task Examples
Delay will be incremented by 1 ms while Width is decremented by 2 Comments The interface is initialized and the HP 8112A is set to the standard settings (see Chapter) Lines 100 to 120 setup period, delay, width, high-level, and low-level and line 130 enables the output.
Page 101 PRINT "Every two seconds delay is incremented by 1 ms and width is decremented" PRINT "by 2 ms . .." PRINT ! Delay and Width loop FOR I=0 TO 10 ! Print the values for the Setup and Hold time OUTPUT Addr;"DEL";New,del;"MS"...
Page 102: Purpose
The main purpose of this program is to demonstrate how to service Purpose an SRQ directly in the program. It also demonstrates how to: initialize the interface of the HP 8112A and set it to the standard setting clear the status byte...
Page 103 SPOLL would be conducted whilst “XXX” is being parsed. At this moment there is neither a syntax error or SRQ active. The resultant SPOLL would be 128, indicating that the HP 8112A command buffer is not empty. (See Chapter 6 Error, fault and status reporting.
Page 104: Purpose
This program demonstrates how to use interrupts to service Purpose Comments Setup section (thes 110 - 120): The interrupt service subroutine Service-srq is set up. SRQs from interface 7 are enabled to cause an interrupt. Main section A SPOLL is conducted to show the value of the STB before the syntax error.
Page 105: Error-Demo
SUB Service,srq PRINT II,,_,,,,_,,,_,,,-,,,-,,,,,,-,,-,,,------------------------- PRINT "SRQ from HP8112A --> Main Program interrupted." PRINT Print,spoll ! read the Status Byte and print the results PRINT PRINT "End of the interrupt routine." ! Enable interrupts again. ENABLE ! The subroutine Print,spoll conducts a SPOLL to read the Status Byte. ! Errors as indicated by the set bits are printed.
Page 106 ! Name of this program: ERROR-DEMO ! This program demonstrates how to determine which error ! are set in the HP8112A's Status Byte. Also it is shown how to ! get a more detailed description of an error with the ! "Interrogate Error"...
Page 107 PRINT WAIT 2 PRINT "The following bits are set in the Status Byte:" PRINT WAIT 2 IF A=0 THEN PRINT II No bit is set." IF BIT(A,7) THEN PRINT ' Bit 7 --> Buffer Not Empty" IF BIT(A,G) THEN PRINT fl Bit 6 -->...
Page 108: Lrn-Demo
Purpose This program demonstrates the Learn String’s usage: Reading the current Learn String with CST Sending the Learn String back to the HP8112A Time taken for transferring the Learn String is printed Recalling a setting from a location is shown (RCLO) Comments There is no direct command in the Learn String which indicates the active parameter of the two modes: DELAY/DOUBLE and...
Page 109 ! clear Status Byte DIM A$[1531 ! The Learn String consists of 153 ASCII characters. PRINT "Recalling setting from location 0 (Standard Setting) . .." OUTPUT 712;"RCLO" PRINT PRINT "Reading the current setting . ..". Oldtime=TIMEDATE OUTPUT 712;"CST" ! read the current setting ENTER 712;A$ DIV .OOl>/lOOO PRINT 'I .
Page 110: Interrog
3. Screen dump of the results printed when running the program INTERROG The current setting of the HP 8112A is: 0001 #,PER 1.00 MS,DBL 200 US,DEL 65.0 NS,DTY 5 0 The current setting of location 5 is: 0001 #,PER 1.00 MS,DBL 200 US,DEL 66.0 NS,D...
Page 111 CLEAR SCREEN CLEAR 712 ! initialize interface and HP8112A ! clear status byte ! Learn String interrogate function CST (Current Setting) DIM Setting$[l531 OUTPUT 712*"CST" ENTER 712;Setting$ PRINT "The current setting of the PRINT Setting$ PRINT PRINT ! Interrogate Parameter Set IRCLO..S OUTPUT 712;"IRCL 5"...
Page 112 OUTPUT 712."IBUR" ENTER 712;Burst$ PRINT "Response after IBUR command: ";Burst$ PRINT PRINT "End of the program INTERROG." LOCAL 712...
Page 113: Testing Performance
Records which follow the test procedures. Test results recorded at incoming inspection can be used for comparison after carrying out maintenance, repair or adjustments. The tests must be performed with the HP 8112A in its normal operating condition, that is, with all shields, connections and the case in place.
Page 114: Test Equipment
HP 5335A Counter 50 MHz, Start/Stop, with OPT 040 TI, A to B Digital Voltmeter HP 3458A DC 0.01 V-50 V, .004% act. HP 3478A Pulse amplitude facility HP 3456 Function Generator HP 8116A 20 MHz, THD 5.1% Digitizing Scope...
Page 115: Period Performance Test
- 1 . 0 0 v 3. Set the counter function control to PER A. 4. Set the HP 8112A Period to the following values and read the actual output from the counter. Record your results on a copy of...
Page 116: Delay Performance Test
Test Record, specified limits are given here and on the Test Record. Counter reading HP 8112A setting Low Limit High Limit 17.0 23.0 10 /is 9.5 ps 10.5 ps 9.5 ms 10.5 950 ms 902.5 ms 997.5 ms Delay Performance...
Page 117: Test Setup
1.2 v Gate Mode 4. Set the HP 8112A Delay and Period to the following values and read the actual output from the counter. Record your results on a copy of the Test Record, specified limits are given here and on the Test Record.
Page 118: Double Pulse Performance Test
0.2% of programmed value flOOps Equipment Digitizing Oscilloscope with Accessory (HP 54121T) Counter (HP 5335A) Cable, 50 R, BNC to BNC, coaxial, 2 each (HP 8120-1839). 20 dB attenuators (Required if counter input impedance # 50 52) Test Setup 1...
Page 119: Test Setup 2
Test Setup 2 Counter (HP 5335A) Figure 8-4. Double Pulse Performance Test 1. Connect the HP 8112A to the oscilloscope as shown in Test Setup 1 2. Set up the HP 8112A as follows: NORM Input Mode Control Mode Transition...
Page 120: Pulse Width Performance Test
PER DBL WID Low Limit High Limit ns 10 ns 17.0 ns 23.0 21.0 #L&3 10 ps 19.ops Connect the HP 8112A to the counter as shown in Test Setup 2 Set the counter as follows: Preset Trigger level Mode PER A...
Page 121: Equipment
1.00 v - 1 . 0 0 v 2. Connect the HP 8112A and oscilloscope as shown in Figure 8-5. 3. Verify that for the following HP8112A WID settings the scope display indicates that the HP 8112A output is within the specified limits.
Page 122: Constant Duty Cycle Performance Test
Pulse width is measured at 50% of pulse amplitude. Note 5. Connect the HP 8112A and counter as shown in Figure 8-6. 6. Set the counter as follows: Trigger level Preset Mode Time A + B Impedance Gate Mode Slope A...
Page 123: Equipment
- 1 . 0 0 v 3. Set the counter to DTY CY A. 4. Set the HP 8112A DTY to the following values and read the actual output from the counter. Record your results on a copy of the Test Record, specified limits are given here and on the Test Record.
Page 124: Output Levels Performance Test
Connected to EXT TRIGGER on rear of DVM Figure 8-8. Output Levels Performance Test Procedure 1. Connect the equipment as shown in the setup figure. Use a 50 R feedthrough termination 0.1%. 2. Set up the HP 8112A as follows: Input Mode NORM Control Mode Transition...
Page 125 For each value of HIL in table, verify that the DVM reading is within the specified limits. Record your results on a copy of the Test Record, specified limits are given here and on the Test Record. Set up the HP 8112A as follows: 65 ns 0.0 v -0.10 v For each value of LOL in table, verify that the DVM reading is within the specified limits.
Page 126: Test Setup
HP 8112A with BNC/SMA Adaptor Figure 8-9. Transition Times Performance Test Procedure 1. Connect the equipment as shown in the setup figure above. 2. Set up the HP 8112A as follows: Input Mode NORM Control Mode P E R 100 ns...
Page 127: Transitions
Transition Linear 0.00 v For the HP 8112A to the settings in the table below, measure the displayed leading edges (LEE) and trailing edges (TRE). Verify that the transition times do not exceed the specified limits. Record your results on a copy of the Test Record, specified limits are given here and on the Test Record.
Page 128: Pulse Performance Test
0.00 v Adjust the oscilloscope so that one pulse fills the display. Examine the HP 8112A output on the scope display in order to verify that the pulse characteristics do not exceed the specified limits as identified in Figure 8-11.
Page 129 6.5 ns T R E 6.5 ns 7. Examine the HP 8112A output on the scope display in order to verify that the pulse characteristics do not exceed the specified limits as identified in Figure 8-11. 8. Record your results on a copy of the Test Record, specified limits are given here and on the Test Record.
Page 130: Trigger,Gate,E.width And E.burst Verification Test
Amplitude Figure 8-11. Pulse Performance Characteristics Trigger,Gate,E.Width and E.Burst Verification Test Characteristics Trigger Minimum 500 mV (p-p) amplitude Minimum 10 ns pulse width Each active input generates one output pulse. Gate External signal enables Period Generator. First output pulse synchronous with external trigger. External Width Restoration of external signal with selectable transition times and output levels.
Page 131: Equipment
Amplitude 2.0 v Offset 0.00 v 4. Using the oscilloscope, adjust the HP 8112A trigger level to allow triggering from the external pulse generator. 5. Verify that each external trigger pulse generates one complete output cycle as shown shown here.
Page 132 TRIG OUTPUT lA7pJ (INPUT 3) 6 . Set the HP 8112A to GATE trigger mode, PER = 900 ns and DTY = 50%. Verify that each gate leading edge releases a train of output pulses and that each cycle is complete. As shown here.
Page 133: Output Mode Verification Test
12. Using the oscilloscope, adjust the HP 8112A trigger level to allow triggering from the negative going edge of the external input signal. 13. Set the oscilloscope sweep speed to 2 ps/division. 14. Verify that each external trigger pulse generates a burst of 50 output pulses as shown here.
Page 134: Equipment
Attenuator 20 dB, 2 W (2 x) (required if counter input impedance 2 50R Procedure 1. Connect the equipment as shown in the setup 1 figure 2. Set up the HP 8112A as follows: Trigger Mode NORM Control Mode Transition...
Page 135: Period Control Verification Test
Slope A Trigger level preset 13. Press the m key on the HP 8112A to simulate an external trigger and verify that the counter counts 472 pulses. 14. Press the (iKK%) key and confirm that the counter reading increments to 473.
Page 136: Procedure
65 ns 2.00 v 0.00 v 3. Vary the power supply (or HP 3324 in DC Mode) between approximately 1 volt and 10 volts, and verify that the counter display indicates a range of periodic times which agree with the specified limits for each of the HP 8112A settings below.
Page 137: Test Setup
50 ns 2.00 v 0.00 v 3. Vary the power supply or HP 3324A between approx 1 volt and 10 volts and verify that oscilloscope display indicates delay time of between 75 ns and 170 ns as shown below. 4. Connect the HP 8112A output to the counter.
Page 138: Width Control Verification Test
7. Vary the power supply between approx 1 volt and 10 volts and verify that for the following HP 8112A settings, the range of times displayed agrees with those specified. HP 8112A Counter setting reading High 100 ns 75 ns...
Page 139: Procedure
0.00 v 3. Set the counter to PULSE A 4. Vary the power supply or HP 3324A between approx 1 volt and 10 volts and verify that for the following HP 8112A settings, the pulse width range agrees with those specified.
Page 140: Test Setup
Control Mode Transition Fixed 200 ps P E R 65 ns D T Y -2.00 v 3. Set up the HP 8116A Pulse/Function Generator as follows: output 50 Hz Frequency Amplitude 16.0 V 0.00 v Offset 4. Verify that the High-level output can be varied between +8 V and -8 V while the -2 V level remains unchanged as shown below.
Page 141: Store And Recall Function Test
6. Set up the HP 8116A Pulse/Function Generator as follows: Squarewave output Frequency 1 kHz Amplitude 2.0 v 0.00 v Offset 7. Verify that the scope display indicates a settling time of less than Figure 8-21. Correct Delay Control Store and Recall...
Page 142: Procedure
HP-IB cable Procedure Note All program statements assume that the HP 8112A is at HP-IB address 12 and that BASIC 5.0/5.1 is being used. 1. Connect the equipment as shown in the setup figure. 2. Use the following program statements to read the HP 8112A...
Page 143 5. Verify that the settings are the same as before, except for the following: PER 10.0 MS DTY IO % HIL 1.50 v 8112A 6. Using the oscilloscope confirm that the HP output has the following form: Square Pulses Period...
Page 144 8-32 Testing Performance...
Page 145 PERFORMANCE TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Generator Serial No: _-----_------_- ____ -- _____ - Report No: -- ________ -_-- ____ ----__-- Date: ----_-----___ Test Facility : Test Conditions : Installed Options : Ambient Temperature : Relative Humidity :...
Page 146: Performance Test Record Page 2 Of 8
PERFORMANCE TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Generator Serial No: ------___------------ ______ Report No: -------------- ____________ Date: __________ --- Test Equipment Description Model No. Serial No. Counter Oscilloscope Digital Voltmeter Function Generator Controller 8-34 Testing Performance PERFORMANCE TEST RECORD Page 2 of 8...
Page 147 PERFORMANCE TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Generator Serial No: ____ -- _______ - _____________ heport No: _____________ - ____ ----___- Date: -----___----- Period 1 Minimum 1 MEASURED 1 Maximum 1 Uncertainty 23.0 ns 23.0 ns 10.5 ps 10.5 ps 10.5 ms...
Page 148 Hewlett-Packard 8112A 50 MHz Pulse Generator PERFORMANCE TEST RECORD: Serial No: -------_--------_-_________ Report No: ---___----- ____ -----__--__ Date: -___------___ Pulse Width Pulse Period Width Minimum MEASURED Maximum Uncertainty 12.5 ns 100 ns 10 ns 7.5 ns Settings MEASURED Maximum Uncertainty 42.0 ps...
Page 149 PERFORMANCE TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Generator Serial No: ______--------------------- Report No: __---_----__---__--------- Date: _------------ Low-Level MEASURED Maximum Uncertainty -0.1 v -0.056 V -0.144 v -0.5 v -0.44 v -0.56 V -1.0 v -0.92 v -1.08 V -5.0 v -4.76 V...
Page 150 PERFORMANCE TEST RECORD: Hewlett-Packard 6112A 50 MHz Pulse Generator Serial No: - ____ - ______ -__-- ______ -__- Report No: _______________ ------_---- Date: _____________ Pulse Performance Fixed Transitioln- MEASURED Uncertainty Characteristic Specification Preshoot Overshoot/Ringing Settling time Specification Characteristic Preshoot 35% of amplitude 3110 mV Overshoot/Ringing Settling time 8-38 Testing Performance...
Page 151 VERIFICATION TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Generator Serial No: -__--_-------- _____________ Report No: ________________ -__-__---- Date: -_--__--_--__ Trigger, Gate, Externgl Width and Burst Modes Trigger Positive trigger initiates one complete output cycle: YES/NO Gate Each gate leading edge releases train of output...
Page 152 VERIFICATION TEST RECORD: Hewlett-Packard 8112A 50 MHz Pulse Ge/nerator Serial No: ---------------- ___________ Report No: _________________ -___-___- Date: ------------_ Delay Control Minimum and Maximum achieved YES/NO 10 ps YES/NO 1000 f.Ls YES/NO 1000 YES/NO Width Control Minimum and Maximum achieved...
Page 153: Adjustment Procedures
Shaper and Offset Adjustment Slope Note Always allow the HP 8112A to warm up for at least 1 hour before starting any adjustment procedures. The Power Supply and Preliminary adjustment procedure must always be carried out after any repairs. If any re-adjustment is required during this procedure then all the remaining procedures must be carried out.
Page 154 Always carry out an adjustment procedure completely and in the order in which it is presented. If the HP 8112A is very badly out of adjustment, turn AlR413 fully clockwise and all other adjustment potentiometers to their mid position. Then carry out all the adjustment procedures.
Page 155 Table 9-1. Adjustment Procedures - Changeable Components (continued) Description Procedure Reference 22 pF Range capacitor Delay Bias adjustment Both influence linearity of open or 4.3 V Delay Generator open or 51.1 kQ used to get A2R14 (DEL 1 ms Adj.) to it’s mid 3.83 kR range used to get A2R13 (DEL 20 ms Adj.) to it’s mid...
Page 156: Test Preparation
Refer to Chapter 1 Introduction for the recommended test equipment and accessories. Test PreparatiFn Refer to Chapter 10.1 Troubleshooting for instructions on how to open up the HP 8112A instrument and prepare for servicing> Control Board Microprocessor Board Figure 9-1. Access to the HP 8112A for Adjustments...
Page 157: Pre Adjustments
2. Connect the HP 8112A main output to the oscilloscope input 4 via 40 dB (2 20 dB) attenuation. 3. Connect TRIGGER OUT of the HP 8112A to the TRIG IN of the oscilloscope, via a 20 dB Attenuator. 4. On the oscilloscope: a.
Page 158: Normal/Complement
9. Set the HP 8112A Transition to FIXED. 10. Set the HP 8112A output to COMPL off. 11. Connect the HP 8112A trigger output to the oscilloscope trigger input via 20 dB attenuation. 12. On the oscilloscope press (Autoscale] and <set for 2 V/div vertically and 200 ps/div.
Page 159: Overshoot & Transition Time Adjustment
COMPL DISABLE Off (=Enable) LIMIT 2. Connect the HP 8112A main output to the oscilloscope input 4, via two 20 dB attenuators (40 dB). 3. Connect the HP 8112A trigger output to the oscilloscope trigger input via 20 dB attenuation.
Page 160 9. Centre the pulse base line vertically (offset = 8 V) and set 10. Set the VARIABLE LEVELS = -5 to +5% 11. Check overshoot < 5% in normal and complement modes. Re-adjust AlC530 if necessary. 12. Set the HP 8112A as follows: Fixed Transition Pulse Width...
Page 161 Take full screen display on the scope. Check that the transition times <4.8 ns in both normal and complement modes. Set the HP 8112A to Linear transition. Measure the transition times are <6.2 ns. Note Transition times can be increased by increasing the overshoot. If...
Page 162: Timing
COMPL DISABLE LIMIT 2. Set the counter for Period measurement. 3. Connect HP 8112A output via a 500 feedthrough to the counter. 4. The typical period accuracy of the period decades is as shown in Figure 9-4. PERIOD Figure 9-4. Decade Accuracy 5.
Page 163: Delay (Double Pulse)
19. Set the counter as follows: Time interval Trigger (both than) 20. Connect HP 8112A Trigger Output to channel A of the counter. 21. Connect HP 8112A Output to channel B of the counter. 22. Set trigger levels to trigger at about 50% of amplitudes.
Page 164 31. Connect HP 8112A Trigger Output via a 20 dB attenuator, to Ext. trigger of the HP 54121A. 32. Connect HP 8112A Output via a 20 dB attenuator to input 4 of the HP 54121A. 33. Press [s) and adjust A2R13 for 18 ns f 0.3 ns at 50% of amplitude.
Page 165: Width Adjustment
10 ns 12. Connect HP 8112A Trigger Output via a 20 dB attenuator, to trigger input of the HP 541218. 13. Connect HP 8112A Output via a 20 dB attenuator to input 4 of the HP 541218. Adjustment Procedures 9-13...
Page 166 14. On the oscilloscope press (s] and adjust A2R8 for 10 ns f 0.2 ns at 50% of amplitude. See Figure 9-5. 15. Alter HP 8112A WID to 99.9 ns. 16. Adjust the low range end with A2R59 for 101 ns f0.2 ns.
Page 167: Procedure
2. Set the counter to TIME Interval A-+B, COM, A i, B t , Trig level 0 V, Z = 50R 3. Connect the HP 8112A main output to channel A of the counter. 4. Observe the counter whilst switching the HP 8112A output from COMPL on and COMPL off.
Page 168: Linear Amplitude
If the DVM does not have a built-in filter, use an external low pass filter, as shown in Figure 9-6. 20. Adjust AlR416 for 0 V f5 mV. Linear Amplitude 21. Set up the HP 8112A as follows: Transition Linear -4.99 v 22.
Page 169: Gauss Amplitude
34. Set up the DVM to read DC voltages up to 10 V. 35. Connect the HP 8112A main output via an exact 50 St 0.1% feedthrough terminator to the DVM, and enable the DVM built-in filter. If the DVM does not have a built in filter, use a low-pass filter as shown in Figure 9-6.
Page 170: Hil C
0.0 v COMPL DISABLE LIMIT 41. Connect the HP 8112A output via an exact 50 R 0.1% feedthrough, to the oscilloscope (HP 54503A). 42. Adjust A2R50 for 0 V amplitude (no signal). 43. Set the HP 8116A Signal Generator as follows:...
Page 171: Slope
Slope Equipment Oscilloscopes (HP 54121T/HP 54503A) 20 dB attenuators (3 x) Procedure 1. Set up the HP 8112A as follows: Trigger Mode NORM Control Mode 5 ms P E R 65 ns D T Y Transition Linear 100 /Ls T R E 500 ps -4.00 v...
Page 172 6. Set the HP 8112A as follows: 7. Connect the HP 8112A Trigger Output to the oscilloscope Trigger Input. 8. Connect the HP 8112A output to input 4 of the oscilloscope. 9. Set the oscilloscope to display one pulse using the Delta t mode.
Page 173 31. Set the HP 8112A as follows: 500 ns 100 ns 100 ns 32. Connect the HP 8112A to the HP 54121A oscilloscope using two 20 dB attenuators. 33. Set the oscilloscope to display one pulse and set it to measure Rise/Fall time.
Page 174 HP 8112R BWRD Al Figure 9-8. Adjustment Points on the Main Board Al 9-22 Adjustment Procedures...
Page 175 ADJUSTMENT POINTS HP 8 112fl BOARD A2 R 2 6 R 3 7 R 3 5 HILC PERIOD WIDTH WIDTH Figure 9-9. Adjustment Points on the (control Board A2 Adjustment Procedures 9-23...
Page 177: Introduction To Servicing
Capacitors inside the instrument may still be charged after the instrument has been disconnected from its external power supply. The HP 8112A contains static-sensitive devices. Ensure that “static-safe” precautions are taken to ATTENTION...
Page 178 5. Check that the case is isolated from the power-cord power-pins in accordance with IEC & VDE. If a problem exists, it must be investigated and fixed before proceeding. 6. Check that the correct line fuse is fitted. 7. Check that all safety covers are fitted. 8.
Page 179: General
Component layouts for each board assembly are also provided. The five board assemblies contained in the HP 8112A are listed in Table 10-l which lists the servicing chapters applicable to each board.
Page 180 Table 10-l. HP 8112A Board Assemblies & Servicing Chapters I Reference 1 C h a p t e r ( s ) 1 Main Board 10.2, 10.3, 10.4 Control Board 10.5, 10.6 10.7 Microprocessor Board Keyboard 10.7 10.7 Display Board...
Page 181: Instrument Overview And Troubleshooting Guide
1 0 . 1 Instrument Overview and Troubleshooting Guide Theory of Operation The block diagram in Figure 10.1-l shows the HP 8112A at a functional level. H P - I B ,,, I N P U T \ KEY BORRII...
Page 182 The ICs and their supporting circuits are covered in more detail in the relevant parts of the later chapters, however, the IC pin identities are given in Figure 10.1-2. TOP VIEW Figure 10.1-2. Custom KS used in the HP 8112A 10.1-2 Instrument Overview and Troubleshooting Guide...
Page 183: Trouble Shooting
Every time the instrument is switched on, or when an EST command Trouble sh;ooting is received on the HP-IB, the HP 8112A executes a self-test. If a fault is detected an error code is displayed, otherwise the instrument is ready for operation. The error code can be used to locate the fault by referring to the following flowchart.
Page 184 10.1-4 Instrument Overview and Troubleshooting Guide...
Page 185: Key Jammed
Key Jammed Possible faulty A3 Processor Board (ROM reset circuit) or power supply fault (restart signal) A front panel key is stuck. The instrument cannot be used until it is freed. RAM Test The microprocessor is unable to load a test pattern into the RAMS or main board, remove the device-bus cable from the main board Al at connector J2 (See Chapter 10.2.
Page 186 RMPLIFIER STRTIC Y E S 10.1-6 Instrument Overview and Troubleshooting Guide...
Page 187: Output Amplifier Tests
Output Amplifier Tests Offset generator is unable to produce positive offset. Possible failure in Output amplifier or offset control circuit U17 to U19, U20 to U22, or U27. See Chapter 10.4. Offset generator is unable to produce negative offset. Possible failures as E21.
Page 188 BURST T E S T S 10.1-8 Instrument Overview and Troubleshooting Guide...
Page 189: Amplitude Tests
Amplitude range 1 (1 V) not possible. Possible faults as in E41. Burst Tests HP 8112A set to produce a burst of 10 pulses of period 250 p.s. Burst counter supplies less than 10 pulses. Possible fault in Burst flip-flop U201 or Burst control circuit U102 to U112. Refer to Chapter 10.6.
Page 191: Servicing The Power Supply
Servicing the Power Supply Theory of Operation The HP 8112A power supply unit occupies part of the main Introduction board Al and consists of the following four parts, as shown in Figure 10.2-l: Line voltage selector and transformer Voltage rectifiers and regulators...
Page 192 Table 10.2-I. Power supply rectifiers The raw voltage outputs are all smoothed by capacitors, as shown in Figure 10.2-3. The following supplies are then fed to voltage regulators, with potentiometers to adjust the final voltage level: Table 10.2-2. Regulated voltage supplies Supply Regulator Adjustor -15 v The smoothed f5 V DC outputs of CRl, which drive the fan, also...
Page 193: Power-Down Detection
(5.1 V) t han its non-inverting input (5 V). When the HP 8112A is switched off, the 5.1 V supply breaks down faster than the 5 V reference because it is loaded by the microprocessor board.
Page 194 10.2-4 Servicing the Power Supply...
Page 195 S E R V I C E M A I N P / O A l B O A R D LINE voLlAaE P/O Al MAIN L I N E MODEL 1 0 . 2 - 2 . MAIN BOARD Al SCHEMATIC 1 0 .
Page 197 P / O A l M A I N B O A R D l 23v Rm l 15v UHPEO...
Page 198 S E R V I C E T O A2/J4 C O N T R O L SO J 6.2V l !w T O A2/J4 CONTROL - 1 6 V 0166 M O D E L W8112A f IWRE 11.2-a Al SCHEWATIC T H E PO%R S U P P L Y 18.2-7...
Page 199: Troubleshooting The Power Supply
Troubleshooting the Power Supply Figure 10.2-4. Detail of wiring to Line Voltage Selector switches Removing the fan Starting with the instrument in its Servicing position: 1. Unplug the red and blue wires connecting the fan to the main board. 2. Remove the four screws securing the fan to the rear of the frame. 3.
Page 200 n ,,4 --- -4c n +) Figure 10.24. Power supply components - Underside of main board Al Note The main component layout and locator for the main board Al are in Chapter 10.4. 10.2-10 Servicing the Power Supply...
Page 201: Servicing The Timing And Slope Generators
Servicing the Timing and Slope Generators Theory of Operation The majority of the timing and slope generation circuit components Introduction are on the main board Al. A small part of the associated circuitry, concerned with burst control, is on the control board A2. Operation of the timing and slope circuits is explained under the following functions: Trigger input...
Page 202: Address Decoder
HILC mode operation. Timing IC The timing ICs used in the HP 8112A are programmable timers which can be used to produce repetition rates, pulse widths and delay times by utilizing a variety of trigger and gate mode inputs.
Page 203: Timing Generation
Figure 10.3-l. Timing IC block diagram Refer to Figure 10.3-l and Figure 10.3-6. The timing IC has an input store containing 8 control bits which control the mode of the IC: Table 10.3-2. IC Digital Control Signals Function Name positive 1 0 C O N T R O L TTL edge on this pin latches all ENABLE...
Page 204: Rate Mode
In TIME mode the ranges are from 10 ns to 99.9 ms and 50 ns to 500ns. In RATE mode, ranges are from 100 MHz to 10 MHz and 20 MHz to 2 MHz. Ranges are selectable as shown in Table 10.3-3. Table 10.3-3.
Page 205: Outputs
Because CUR REF, FRQ IN and TIME IN are virtual earth inputs, the external input currents can be produced by a voltage source and series resistance. The control mode functions (PERC, DELC, WIDC) are produced by feeding the conditioned control input voltage to the TIME IN input of the relevant timing IC.
Page 206: Delay Generator
The IC is either free running or triggered by the EXT INPUT, depending on the state of the internal trigger mode latches (data from LD5 to LD7). The inverse output OUT is passed to the trigger amplifier (Chapter 10.7) for subsequent output as TRIG OUT. Normal output OUT, is passed via level shifter Q200 to the delay generator trigger input.
Page 207: Slope Generation
Slope Generation Figure 10.3-3. Slope IC block diagram Refer to Figure 10.3-5 and Figure 10.3-3. When triggered by the output of the width generator, the Slope IC U301 operates in one of two transition modes. Fixed Transition In fixed mode (fixed 4.5 ns transitions), an ECL trigger output is used by the Shaper IC (See Chapter 10.4) to produce fixed transition time output pulses.
Page 208: Current Sources
Current Sources External constant current sources on the control board A2 provide I up ref and kown d. When a rising edge is detected at TRIG IN, Q303 is switched on via the internal buffer to enable one of the internal or external ramp capacitors to charge up linearly by I,, (derived from Iur, ref) t a a rate set by the LEE DAC on the control board.
Page 209 ADDRESS DECODER MODE DECODER FROM A3 MICROP. BD FROM FRONT P A N E L F R O M F R O N T P A N E L...
Page 210 S E R V I C E RANGE DECODER BURST FF FROM CONTROL 0D l El 1 1 4 C l 1 2 C l “ 0.12 so.hs +A” 51.1 CONTROL MODE SELECTOR 1 0 . 3 - 4 .
Page 211 F R O M A 2 CONTROL BOARD PER 100 GENERATOR G E N E...
Page 212 ERROR -FEEDBACK LEVEL CHECK AUTO VERNIER FEEDBACK (LO71 DELAY. 151112121415151712 10.3-11 SERVICING TIE...
Page 213 RAMP CURRENT SOURCES RAMP ! FROM A2 CONTROL BOARD 21DOWN RANGE SWITCHING >lus...
Page 214 S E R V I C E l 16v N. 0. REFERENCE Al -TIC Al -TIC 10.3-13 10.3-13 T I N I N Q AN0 SLOPfZ...
Page 215: Troubleshooting
Troubleshooting Note If an error code is being displayed by the HP 8112A you must press a key, (LCL) for example, to return the microprocessor to normal operation before troubleshooting. The component layout and locator for the main board Al is at the end of this chapter.
Page 217: Control Mode Selection
Table 10.3-6. Address Decoder Signatures Free run Area Description Connector Mnemonic S.A. Sub coded address Sub coded address Sub coded address 8759 Enable address decoder Data load signal for U500 w s 2 see chapter 10-4 Error feedback gate signal signature Check the of address decoder outputs against those...
Page 218: Period Generator
The level check output (LCO) on pin U101/16 is LOW in normal mode and HIGH during self test. Period Generator To check operation of the Ext. Input Circuit: 1. Set up the HP 8112A as follows: Mode Trig Trig Slope...
Page 219 7 0 n s Figure 10.3-g. Period Generator ramp signal pin 20 3. Check the trigger output signal at pin 21 of U200 against Figure 10.3-10. 4. Check the signal being sent to the delay generator IC220 at TPl against Figure 10.3-10. OUTPUT ON PIN2 1 OUTPUT TO DELRY GENERRTOR ON TPl...
Page 220: Delay Generator
PER Setting 1 Voltage across R212 9.99 ins -0.016 V Delay Generator 1. Set up the HP 8112A as follows: 200 ps 2. Check the input signal from the period generator pin 7 of U220 against Figure 10.3-11. DEL 650us DEL 200us Figure 10.3-11.
Page 221: Width Generator 1
6 . Verify that voltage at U220 pins 1 , 4 and 5 are at virtual ground Delay Vernier Current can be checked by measuring the voltage Note across R226. 7. Set HP 8112A PER to 20 ms Delay 8. Check the Generator levels against Table 10.3-13 Table 10.3-13.
Page 222 Figure 10.3-14. Width Generator ramp signal 4. Check the signal being sent to the slope generator IC at TP3 against Figure 10.3-15. 200us Figure 10.3-15. Width Generator output 5. Check the Width Generator operation against Table 10.3-14 and Table 10.3-15 Table 10.3-14.
Page 223: Slope Generator
8. Check signal levels against Table 10.3-15 Table 10.3-15. Width Generator Signal Levels Slope Generator 1. Set the HP 8112A to RCL 0 and press the @ key: 2. Check the input signal from the width generator at pin 1 of U301 against Figure 10.3-16 3.
Page 224: Range Decoder
5. Verify that the voltages at U301 pins 11/15 are at REF voltage (typ. +1.85 V) 6. Verify that the voltage at U301 pin 13 is at TTL LOW level (typ. Range Decoder 1. Check the range decoder against Table 10.3-16. Table 10.3-16.
Page 225: Servicing The Shaper And Output Amplifier
10.4 Servicing the Shaper and Output Amplifier Theory of Operation Introduction The shaper and output amplifier circuits are located on the main board Al and are divided into the following parts: Bus Latch Shaper IC Current Mirror Signal Output Amplifier Output Attenuator Trigger Output Amplifier These circuits are the last in the signal path.
Page 226: Wave Forming
Figure 10.4-l. Shaper IC Block Diagram Table 10.4-l. Shaper IC Output Modes output Inputs Input Signal Selected Linear Differential Differential Shaped Not used EECL (0 V, -0.6 V) Fast Pulse The main inputs are differential current inputs INP or INP. The single-ended EECL voltage input (0 V to -0.6 V) generates an output pulse with fast, but fixed, transition times.
Page 227: Output Mode
Figure 10.4-2, and depends on QlA and QlB being a matched pair so that I, = Ib. In the HP 8112A QlA = Q400A, QlB = Q400B and Q2 = Q402. In fixed mode, Q403 4s turned on, switching the R430/C409 combination into the ‘current mirror in order to improve its...
Page 228: Pre-Attenuator
P A I R ) OUT=2 A I Figure 10.4-2. Current Mirror Pre-Attenuator The pre-attenuator circuit is controlled by the microprocessor via latch U500. Logic signals Kl - K4 control relays K500 - K503 to provide three levels of attenuation according to the range of output voltage required.
Page 229: Input
R f b OFFSET CURRENT OFFSET VOLTRGE CONTROL CONTROL Figure 10.4-3. Simplified Output Amplifier circuit The circuit is effectively an inverting amplifier with a voltage gain given by The main HF amplifier consists of the discrete transistors Q501 - Q513 and their related components on Figure 10.4-5. The offset current error of the amplifier is compensated for by the offset-current control amplifier U501.
Page 230: Voltage Gain
In normal mode the TRIG OUT signal is a 50% duty cycle square wave at the same frequency as the main HP 8112A output. In TRIG and GATE modes, the TRIG OUT signal is a pulse-shaped equivalent of the trigger input.
Page 231 CURRENT MIRROR 1 4 . 7 14.7 N.O. PRE-ATTENUATOR M O D E L HP61126 M O D E L HP61126 FIGURE 10.4-4. Al SCHENATIC MAIN SOAR0 MAIN SOAR0 Al SlXEMATIC 10.4-7 10.4-7 WTPUT AMPLIFIER WTPUT AMPLIFIER...
Page 232 4 . M FROM A2 CONTROL...
Page 233 S E R V I C E a. 47u TRIGGER OUTPUT AMPLIFIER FI SURE 10.4-S. A l SCEMATIC 1 0 . 4 - 9...
Page 234 A l M A I N B O A R D OUTPUT AMPLIFIER l 22v OFFSET l 1SV CURRENT COMPENSATION OFFSET VOLTAGE CONTROL -22V...
Page 235: Troubleshooting
Troubleshooting Note If an error code is being displayed by the HP 8112A you must press a key, a for example, to return the microprocessor to normal operation before troubleshooting. The component layout and locator for the main board Al is at the end of this chapter.
Page 236 GAUSSIAN. 7. Check the output on TP6 against Figure 10.4-9 Figure 10.4-g. Shaper IC Output (LINEAR) 8. Change the HP 8112A HIL to +0.99 V and transition mode to FIXED. 9. Check the output on TP6 against Figure 10.4-10 Figure 10.4-10. Shaper IC Output (FIXED, HIL +0.99 V) 10.4-12...
Page 237: Transition Mode And Output Control Signals
Fixed Linear Gauss output Mode COMPL Check the amplitude-vernier control-voltage with the HP 8112A Shaper IC HIL and LOL settings as indicated in Table 10.4-4. The voltage is Amplitude-vernier measured at the board connector side of R422. Control-voltage Table 10.4-4. Amplitude-vernier Control-voltages...
Page 238: Offset-Vernier Control-Voltage
-4.8 V -4.5 v -5.5 v -7.9 V -8.0 V Output Amplifier Do not operate the HP 8112A without the heatsinks fitted on Caution board Al If you need to replace one or more of the transistors Q505 - Q513,...
Page 239 7. If there is distortion, check the output-amplifier input signal at TP4. Then do the following: a. Set up the HP 8112A as follows: -8.0 v b. If the input signal is clean but the leading edge of the output signal is distorted, check Q503 and Q505.
Page 240 Servicing the Shaper and Output Amplifier...
Page 241 - 2 3 v C l 4 1 FITTED M I C UlEE, CA19 FITTED LWER SERVICING TX si=wm FM) WmJT WXIFIER...
Page 242 MAIN Al BD AY u 1 4 1 C R 1...
Page 243 MODEL HPB112A G R I C !EF . ? E F . G R I D ?EF . G R I D ?EF . GRIT: ?EF. G R I D ? E F . G R I D G R I D 0 3 0 6 R117 R321...
Page 245 1 0 . 5 Servicing the Control Board Theory of Operation The main function of the control board A2 is to convert digital Introduction control data into analog control signals used on the main board Al. The main board supplies power to the control board and the standard control board is divided into the following areas: Timer circuit Address decoders...

HP 8112A Operating, Programming And Servicing Manual

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