Polar Instruments CITS Series Service Manual

Controlled impedance test systems

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Polar CITS Series Controlled Impedance Test Systems

CITS100 – 500s and 800s

Service Manual

(includes A models)

Polar Instruments Ltd

Polar Instruments Ltd.

Garenne Park

St. Sampson

Guernsey

Channel Islands

GY2 4AF

ENGLAND

http://www.polar.co.uk

Fax: +44 (0)1481 252476

email: mail@polarinstruments.com

MAN 143-0506

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Page 1 Polar CITS Series Controlled Impedance Test Systems CITS100 – 500s and 800s Service Manual (includes A models) Polar Instruments Ltd Polar Instruments Ltd. Garenne Park St. Sampson Guernsey Channel Islands GY2 4AF ENGLAND http://www.polar.co.uk Fax: +44 (0)1481 252476 email: mail@polarinstruments.com...
Page 3 Reliability statistics indicate that if the TDR head is damaged, it is likely to have arisen from misuse (e.g. static damage or similar) and as these circumstances are outside Polar Instruments’ control, any further failures will not be covered by warranty.
Page 5 DECLARATIONS European Community Directive Conformance Statement Refer to the Operator Manual to determine conformance with European Community Directives. DECLARATIONS  i CITS Service Manual...
Page 6: Safety
SAFETY WARNING: The service instructions contained in this manual are for use by qualified electronic service personnel only. WARNING The LIVE and NEUTRAL lines on this unit are BOTH fused. When the unit is connected to its supply, the opening of covers or removal of panels is likely to expose dangerous voltages.
Page 7: Power Supply
Use only the accessories (e.g. test probes and clips) provided by Polar Instruments. The instrument must be maintained and repaired by a skilled electronics technician in accordance with the manufacturer’s instructions.
Page 8: Caution
CAUTION Electrical Isolation Always disconnect the board under test from the local mains supply (including ground) before using this instrument. Static Sensitive Devices This unit contains Static Sensitive Devices. Static discharge can damage some electronic components. Care must be taken when handling these components. Observe appropriate precautions to avoid damage.
Page 9: Specifications
SPECIFICATIONS Test parameters 0 – 150 Controlled Impedance Measurement Range Measurement Accuracy 1% at 50 Measurement Accuracy CITS500s (32 bit) 1% at 50 1.25% at 75 1.5% at 28 and 100 Vertical Display Ranges 1, 2, 5, 10, 20, 50/division Horizontal Display Ranges Automatically set by software Testable Trace Lengths...
Page 10: Environmental Operating Conditions
ENVIRONMENTAL OPERATING CONDITIONS The instrument is designed for indoor use only under the following environmental conditions: Altitude Up to 2000m Temperature +5°C to +40°C ambient RH 80% maximum at 31°C — derate Relative humidity linearly to 50% at 40°C Mains borne transients As defined by Installation Category II (Overvoltage Category II) in IEC60364-4-443...
Page 11: Physical Characteristics (Excluding Accessories)
PHYSICAL CHARACTERISTICS (EXCLUDING ACCESSORIES) Temperature Operating 10°C to 30°C Storage 0°C to 50°C Dimensions CITS100/200/500s 443 mm (17.44 in.) wide 114 mm (4.48 in.) high 280 mm (11.02 in.) deep Weight 5.0 kg (11 lb.) CITS500s 2/4/8a 446 mm (17.6 in.) wide 132 mm (5.2 in.) high 300 mm (11.81 in.) deep Weight...
Page 13: Table Of Contents
CONTENTS DECLARATIONS European Community Directive Conformance Statement ..i SAFETY WARNING ..................ii GROUNDING ................... ii POWER SUPPLY ................iii OPERATION ................... iii CAUTION ..................iv SPECIFICATIONS ENVIRONMENTAL OPERATING CONDITIONS POWER REQUIREMENTS ............. vi PHYSICAL CHARACTERISTICS (EXCLUDING ACCESSORIES).vii SYMBOLS CONTENTS MAINTENANCE OF INSTRUMENTS MAINTENANCE AND CALIBRATION OF INSTRUMENTS ...
Page 14 CITS500 CALIBRATION PROCEDURE CALIBRATION PROCEDURE ............21 Equipment required ............. 21 Impedance Check ..............21 Adjust +12V supply on main board ........22 Check –12V supply on main board ........22 Static Damage check ............22 Set up for Testing Operation with the PC ......23 Configure system ..............
Page 15 CITS500s (32bit) Test Files ..........40 CITS500sa/800s MODELS CALIBRATION PROCEDURE CALIBRATION PROCEDURE ............41 Equipment required ............. 41 Instrument Power Up Check ..........42 Adjust +12V supply on main board ........42 Check –12V supply on main board ........42 Set up for Testing Operation with the PC ......
Page 17: Maintenance Of Instruments
MAINTENANCE OF INSTRUMENTS MAINTENANCE AND CALIBRATION OF INSTRUMENTS Calibration Procedure The Calibration Procedure is used to check and, if necessary, adjust the instrument’s calibration settings. The Calibration Procedure and rectification of defects should only be carried out by qualified technician. Recommendations for Routine Maintenance To maintain the calibration of an instrument it is recommended that its Calibration Procedure is carried out at...
Page 19: Cits100/200 Calibration Procedure
CITS100/200 CALIBRATION PROCEDURE WARNING: Hazardous voltages are exposed on the PCB when the cover is removed. This procedure should only be performed by a technically qualified person aware of the hazards and taking all reasonable care. CALIBRATION PROCEDURE Allow the instrument to warm up for at least one hour prior to carrying out this procedure.
Page 20: Instrument Power Up Check
Instrument Power Up Check Adjust +12V supply on Main board 1. Set the DMM for 20V DC and connect it across C9031. This is located at the rear of the Main board — see the diagram below. 2. Adjust trimmer pot R9032 for +12.0V. R9032 +12V Ad just...
Page 21: Set Up For Testing Operation With The Pc
4. Adjust R1042 on the CITS Front end board (see CITS Front End Board diagram) so that the base of the square wave is at zero volts. Set up for Testing Operation with the PC 1. Connect the CITS to the PC with the RS232 cable and run the CITS software.
Page 22: Zero Offset Adjust (Fine)
Zero offset adjust (fine) 1. Double click on Cal on Demand in the status bar at the bottom of the main screen. A dialogue box will appear. Click on OK to enter the diagnostic routine. Two buttons Calibrate and End Cal will appear in the display. 2.
Page 23: Calculate Calibration Constant
Calculate Calibration Constant When determining the instrument’s Calibration Constant ensure the instrument panels are fitted and take the average of five measurements. Take the known impedance of the airline and the average measured value from the statistics box on the PC screen and use these to calculate the calibration constant:–...
Page 25: Cits500 Calibration Procedure
CITS500 CALIBRATION PROCEDURE CALIBRATION PROCEDURE Equipment required Calibrated Digital Multimeter Calibrated Oscilloscope PC with current CITS Windows S/W (FSW152) Calibrated 50  airline 50  terminator SMA cable, 50  (WMA258) Impedance Check Check the CITS500 line setting and connect to correct supply.
Page 26: Adjust +12V Supply On Main Board
Adjust +12V supply on main board Set the DMM for 20V DC and connect it across C9031. This is located at the rear of the main board — see the diagram below. Adjust trimmer pot R9032 for +12.0V. R9032 +12V Ad just –12V C9035...
Page 27: Set Up For Testing Operation With The Pc
6 0 0 m V Set up for Testing Operation with the PC 1. Connect the CITS500 to the PC with an RS232 cable. 2. Plug a footpedal into the CITS500. 3. Connect the airline to the UUT front panel with the SMA cable.
Page 28: Zero Offset Adjust (Fine)
Ensure the CITS500 has undergone a 1 hour warm-up period before continuing with calibration. In the remaining steps the instrument must stand horizontally with top and bottom panels fitted before making measurements Zero offset adjust (fine) 1. Next double click on Cal on Demand in the status bar at the bottom of the main screen.
Page 29: Calculate Reference Impedance
Calculate Reference Impedance Perform 5 further tests and note the average measured value (from the statistics box on the PC screen) of each test. The difference between the highest and lowest reading should not be more than 0.2 . Calculate the average of the 5 readings and use this as the average measured value to calculate the reference impedance: Reference impedance = Starting impedance + True impedance of airline –...
Page 30: Enter Horizontal Offset And Reference Impedance
Enter horizontal offset and reference impedance 1. Select Help|About. 2. Double-click on the CITS icon at the top left of the screen. 3. Enter the following information:  Calculated value of the reference impedance to two decimal places (e.g. 49.90  ). ...
Page 31: Cits500 Test Files
CITS500 Test Files CAL.TST Impedance 50 ohms Tolerance Probe Length 37.00 inches Test From 5.5 inches Test To 7.5 inches Distance units Inches Ohms Per Div Loss Compensation Default Default Differential Test Method Normal Enhanced Accuracy HORZ500.TST Impedance 50 ohms Tolerance 100% Probe Length...
Page 33: Cits500S (16-Bit) Calibration Procedure
CITS500s (16-bit) CALIBRATION PROCEDURE CALIBRATION PROCEDURE Equipment required Calibrated Digital Multimeter Calibrated Oscilloscope PC with current CITS Windows S/W (FSW159) Calibrated 50  airline 50  terminator SMA cable, 50  (WMA258) TP1030 R1042 CITS Front End Board Instrument Power Up Check Power up the instrument and check the green "BUSY"...
Page 34: Check -12V Supply On Main Board
R9032 +12V Ad just –12V C9035 U9030 +12V C9031 Check –12V supply on main board Connect the DMM across C9035 and measure the –12V supply voltage. Check that this is in the range –11.8 to – 12.2V. Set up for Testing Operation with the PC 1.
Page 35: Zero Offset Adjust (Fine)
5. Press Save, close down the CITS500s software and restart the program. 6. Load the test file CAL.TST. 7. Choose Open from the File menu and highlight CAL.TST. Select OK to load this test file. In the following steps the instrument must stand horizontally with top and bottom panels fitted before making measurements Zero offset adjust (fine) 1.
Page 36: Calculate Reference Impedance
Calculate Reference Impedance Perform 5 further tests and note the average measured value (from the statistics box on the PC screen) of each test. The difference between the highest and lowest reading should not be more than 0.2 . Calculate the average of the 5 readings and use this as the average measured value to calculate the reference impedance: Reference impedance = Starting impedance + True impedance of airline –...
Page 37: Enter Horizontal Offset And Reference Impedance
Enter Horizontal Offset and Reference Impedance 1. Select Help About. Double-click on the CITS icon at the top left of the screen. Press Go. 2. Enter:  Calculated value of the reference impedance to two decimal places (e.g. 49.90  ). ...
Page 38: Cits500S Test Files
CITS500s Test Files CAL.TST Impedance 50 ohms Tolerance Probe Length 37.00 inches Test From 5.5 inches Test To 7.5 inches Distance units Inches Ohms Per Div Loss Compensation Default Default Differential Test Method Normal HORZ500s.TST Impedance 50 ohms Tolerance 100% Probe Length 34.00 inches Test From...
Page 39: Cits500S (32-Bit) Calibration Procedure
CITS500s (32-bit) CALIBRATION PROCEDURE CALIBRATION PROCEDURE Equipment required Calibrated Digital Multimeter Calibrated Oscilloscope PC with current CITS500s (32bit) Software (FSW165) Offset Adjust Test File SMA cable (WMA258) TP1030 R1042 CITS Front End Board Input terminators check Using a DVM on 200 Ohms range measure the input resistance at each SMA connector, measuring between the centre conductor and the threaded outer sleeve.
Page 40: Adjust +12V Supply On Main Board
Measure the power supply levels again and check they are within ranges specified in the table below. Test Point Nominal Minimum Maximum TP23 +4.85 +5.25 TP26 +15V +14.5 +15.5 –15V –14.5 –15.5 TP29 –5V –4.85 –5.25 TP25 Adjust +12V supply on main board Set the DMM for 20V DC and connect it across C9031.
Page 41: Configure System
Configure system Select ‘Diagnostics’ from the ‘Utilities’ menu, double-right- click on the CITS Icon while holding down the ‘Ctrl’ key. Press ‘Toggle Relay State’. Press ‘Ok’. CITS500s (32-bit) CALIBRATION PROCEDURE  37 CITS Service Manual...
Page 42: Static Damage Check
Static Damage check Set the oscilloscope as follows: CH1 100mV/div vertical DC coupling 50 s/div horizontal Connect a 1x probe to CH1 of the oscilloscope. Probe the centre conductor of the SMA connector on end of the SMA cable. A waveform similar to the following diagram should be displayed with no visible vertical jitter.
Page 43: Impedance Measurement Calibration
IMPEDANCE MEASUREMENT CALIBRATION Equipment required PC with current CITS500s (32-bit) Software (FSW165) v8.30+ Two calibrated 28  airlines * Two calibrated 50  airlines * Two calibrated 75  airlines * Two calibrated 100  airline * 50  termination A new set of SMA cables (WMA258 is a pair) * Alternatively, use the ACC229 CITS Verification Kit NOTE: Run the CITS for at least 1 hour to stabilise, ensuring...
Page 44: Calibrating Instrument
Calibrating the instrument 1. Press ‘Set Internal Reference’. 2. For each pair of airlines: 28 , 50 , 75  and 100   Connect the airlines to the SMA cables.  Select ‘Single Ended Ohm’. <XX>  Press Check and enter value of MAIN airline. ...
Page 45: Cits500Sa/800S Models Calibration Procedure
CITS500sa/800s MODELS CALIBRATION PROCEDURE CALIBRATION PROCEDURE Equipment required Calibrated Digital Multimeter Calibrated Oscilloscope PC with current CITS500s (32bit) Software (FSW165) Offset Adjust Test File SMA cable (WMA258) TP1030 R1042 CITS Front End Board CITS500sa/800s MODELS CALIBRATION PROCEDURE  41 CITS Service Manual...
Page 46: Instrument Power Up Check
Input terminators check Using a DVM on 200 Ohms range measure the input resistance at each SMA connector, measuring between the centre conductor and the threaded outer sleeve. The resistance must not exceed 70 Ohms. If out of spec., then replacement of the relay will be needed.
Page 47: Set Up For Testing Operation With The Pc
R9032 +12V Ad just –12V C9035 U9030 +12V C9031 Set up for Testing Operation with the PC Connect the UUT to the PC with an RS232 cable. Plug a foot pedal into the CITS500s. Connect the SMA cable to the UUT front panel MAIN channel.
Page 48: Static Damage Check
Static Damage check Set the oscilloscope as follows: CH1 100mV / DIV vertical DC coupling 50 s / DIV horizontal Connect a 1x probe to CH1 of the oscilloscope. Probe the centre conductor of the SMA connector on end of the SMA cable.
Page 49: Impedance Measurement Calibration
IMPEDANCE MEASUREMENT CALIBRATION Equipment required PC with current CITS500s (32-bit) Software (FSW165) Two calibrated 28  airlines * Two calibrated 50  airlines * Two calibrated 75  airlines * Two calibrated 100  airline * 50  termination A new set of SMA cables (WMA258 is a pair) * Alternatively, use the ACC229 CITS Verification Kit NOTE: Run the CITS for at least 1 hour to stabilise, ensuring that the power is NOT removed before proceeding and that...
Page 50: Calibrating Instrument
Calibrating the instrument This procedure will calibrate the instrument against all four airline values in single-ended and differential modes. 1. Essential step! Press ‘Set Internal Reference’. 2. Start with the 28  airline and proceed through the 50 , 75  and 100 : Single-ended tests 3.
Page 51: Cits500S (32Bit) Test Files
CITS500sxa (32bit) Test Files Offset Adjust Impedance 50 ohms Tolerance Probe Length 39.00 inches Test From 3.0 inches Test To 7.0 inches Distance units Inches Ohms Per Div Loss Compensation Default Default Differential Test Method Absolute CITS500sa/800s MODELS CALIBRATION PROCEDURE  47 CITS Service Manual...
Page 53: Dismantling Instructions
DISMANTLING INSTRUCTIONS To free the covers, first prise off the caps in the recesses in the side mouldings. Remove the screws and lift away the mouldings. Note: the CITS covers are attached to the main body of the instrument by safety ground cables. To disconnect the safety ground cables detach the push-on connector from the tab bolted to the cover.
Page 54: Reassembly
Reassembly With the instrument face down, supported by books or blocks to prevent damage to the SMA connectors, refit the cover and push down to engage the front panel. Replace the 12 screws, fitting all screws before finally tightening them up. 50 ...
Page 55: Line Voltage Selection And Fuse Changing
LINE VOLTAGE SELECTION AND FUSE CHANGING WARNING: There are hazardous voltages inside the instrument when connected to its power supply. REMOVE THE POWER CORD before touching any part of the line input circuit. Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge.
Page 56: Replacing Fuses
REPLACING FUSES Line Fuse If a line fuse failure is suspected: Disconnect the power cord. On early instruments locate the line fuse on the rear of the instrument. On later instruments remove the top cover and locate the line and neutral fuses on the Power Supply printed circuit board.
Page 57: Maintenance And Cleaning
Do not spray cleaners directly onto the instrument. TECHNICAL SUPPORT For technical support contact your local Polar Instruments distributor or Polar Instruments Ltd. at the address at the front of this manual. INSTRUMENT REPAIR If it becomes necessary to repair the instrument, in the first instance contact the Polar Instruments distributor in your country.
Page 58: Schematics
SCHEMATICS The following schematics are covered: CITS100 CITS200 CITS500 CITS500s CITS500s4 CITS100s CITS500s2a CITS500s4a CITS500s8a 54  SCHEMATICS CITS Service Manual...
Page 59: Parts
PARTS Safety critical parts The following components are critical to the continued safe operation of the equipment. These parts must be replaced only with approved parts obtained from Polar Instruments Ltd. or their distributors. Power cord Power inlet connector Fuses and holders...

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