Fluke 2680a User manual

268XA

Data Acquisition System/Data Logging System

Service Manual

PN 1883791

November 2002

All product names are trademarks of their respective companies.

Limited Warranty and Limitation of Liability

Each Fluke product is warranted to be free from defects in material and workmanship under

normal use and service. The warranty period is one year and begins on the date of shipment.

Parts, product repairs and services are warranted for 90 days. This warranty extends only to the

original buyer or end-user customer of a Fluke authorized reseller, and does not apply to fuses,

disposable batteries or to any product which, in Fluke’s opinion, has been misused, altered,

neglected, contaminated, or damaged by accident or abnormal conditions of operation or

handling.

Fluke warrants that software will operate substantially in accordance with its functional

specifications for 90 days and that it has been properly recorded on non-defective media. Fluke

does not warrant that software will be error free or operate without interruption. The software is

neither intended nor warranted for use in medical or any other applications where human safety

may be a concern.

Fluke authorized resellers shall extend this warranty on new and unused products to end-user

customers only but have no authority to extend a greater or different warranty on behalf of Fluke.

Warranty support is available only if product is purchased through a Fluke authorized sales outlet

or Buyer has paid the applicable international price. Fluke reserves the right to invoice Buyer for

importation costs of repair/replacement parts when product purchased in one country is submitted

for repair in another country.

Fluke’s warranty obligation is limited, at Fluke’s option, to refund of the purchase price, free of

charge repair, or replacement of a defective product which is returned to a Fluke authorized

service center within the warranty period.

To obtain warranty service, contact your nearest Fluke authorized service center to obtain return

authorization information, then send the product to that service center, with a description of the

difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in

transit. Following warranty repair, the product will be returned to Buyer, transportation prepaid

(FOB Destination). If Fluke determines that failure was caused by neglect, misuse, contamination,

alteration, accident or abnormal condition of operation or handling, including overvoltage failures

caused by use outside the product’s specified rating, or normal wear and tear of mechanical

components, Fluke will provide an estimate of repair costs and obtain authorization before

commencing the work. Following repair, the product will be returned to the Buyer transportation

prepaid and the Buyer will be billed for the repair and return transportation charges (FOB

Shipping Point).

THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL

OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY

IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

CONSEQUENTIAL DAMAGES OR LOSSES AND/OR PROFITS, INCLUDING LOSS OF DATA,

ARISING FROM ANY CAUSE OR THEORY.

Since some countries or states do not allow limitation of the term of an implied warranty, or

exclusion or limitation of incidental or consequential damages, the limitations and exclusions of

this warranty may not apply to every buyer. If any provision of this Warranty is held invalid or

unenforceable by a court or other decision-maker of competent jurisdiction, such holding will not

affect the validity or enforceability of any other provision.

Fluke Corporation Fluke Europe B.V.

P.O. Box 9090 P.O. Box 1186

Everett, WA 98206-9090 5602 BD Eindhoven

U.S.A. The Netherlands

2/02

WCaution

This is an IEC safety Class 1 product. Before using, the ground

wire in the line cord or rear panel binding post must be connect

to an earth ground for safety.

Interference Information

This equipment generates and uses radio frequency energy and if not installed and used in strict

accordance with the manufacturer’s instructions, may cause interference to radio and television reception. It

has been type tested and found to comply with the limits for a Class B computing device in accordance with

the specifications of Part 15 of FCC Rules, which are designed to provide reasonable protection against

such interference in a residential installation.

Operation is subject to the following two conditions:

•This device may not cause harmful interference.

•This device must accept any interference received, including interference that may cause undesired

operation.

There is no guarantee that interference will not occur in a particular installation. If this equipment does cause

interference to radio or television reception, which can be determined by turning the equipment off and on,

the user is encouraged to try to correct the interference by one of more of the following measures:

•Reorient the receiving antenna

•Relocate the equipment with respect to the receiver

•Move the equipment away from the receiver

•Plug the equipment into a different outlet so that the computer and receiver are on different branch

circuits

If necessary, the user should consult the dealer or an experienced radio/television technician for additional

suggestions. The user may find the following booklet prepared by the Federal Communications Commission

helpful: How to Identify and Resolve Radio-TV Interference Problems. This booklet is available from the U.S.

Government Printing Office, Washington, D.C. 20402. Stock No. 004-000-00345-4.

SAFETY TERMS IN THIS MANUAL

This device has been designed and tested to meet the requirements of EN61010-1

(Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory

Use). It is an Installation Category II device intended for operation from a normal single

phase supply. The DIO relay controls are rated to 250 V ac CAT I and should not be

used in applications that exceed that rating. This Users Manual contains information,

warnings and cautions. Use of this equipment in a manner not specified herein may

impair the protection provided by the equipment.

Measurement category I is for measurements performed on circuits not directly

connected to MAINS. Examples are measurements on circuits not derived from MAINS,

and specially protected (internal) MAINS derived circuits.

Measurement category II is for measurements performed on circuits directly connected

to the low voltage installation. Examples are measurements on household appliances,

portable tools and similar equipment.

WWARNING statements identify conditions or practices that could result in personal

injury or loss of life.

CAUTION statements identify conditions or practices that could result in damage to

equipment.

SYMBOLS MARKED ON EQUIPMENT:

WARNING Risk of electric shock.

Ground (earth) terminal.

Protective ground (earth) terminal. Must be connected to safety earth

ground when the power cord is used.

Attention. Refer to the manual. This symbol indicates that information

about usage of a feature is contained in the manual. This symbol

appears on the Universal Input Module and in the following two places

on the device rear panel:

1. Ground Binding Post (to the left of the line power connector).

2. Alarm/Trigger I/O and Digital I/O connectors.

AC POWER SOURCE

The device is intended to operate from an ac power source that will not apply more than

264 V ac rms between the supply conductors or between either supply conductor and

ground. A protective ground connection by way of the grounding conductor in the power

cord is required for safe operation.

XWWARNING

Use the proper fuse. To avoid fire hazard, for fuse replacement

use only a 1/2 ampere, 250 V time delay line fuse.

DC POWER SOURCE

The device may also be operated from a 9 V to 45 V dc power source when either the

rear panel ground binding post or the power cord grounding conductor is connected

properly. The input is protected by a 4 ampere fuse internal to the device. This fuse

should only be replaced by a qualified Fluke technician.

GROUNDING THE DEVICE

The device utilizes controlled overvoltage techniques that require the device to be

grounded whenever normal mode or common mode ac voltages or transient voltages

may occur. The enclosure must be grounded through the grounding conductor of the

power cord, or if operated on battery with the power cord unplugged, through the rear

panel ground binding post.

USE THE PROPER POWER CORD

Use only the power cord and connector appropriate for the voltage and plug

configuration in your country.

Use only a power cord that is in good condition.

Refer power cord and connector changes to qualified service personnel.

XWWARNING

To avoid possible electric shock or damage to the device:

•Read manual before operating.

•Do not position device so that air flow through side vents is

restricted.

•Do not use in a manner not specified in this manual or

safety protection may be impaired.

•Disconnect power cord and ALL other inputs before

replacing a fuse.

•Position the device where power cord can be disconnected.

•Do not exceed maximum voltages.

XWWARNING

DO NOT OPERATE IN EXPLOSIVE ATMOSPHERES

To avoid personal injury or death, do not remove the device cover without first removing

the power source connected to the rear panel. Do not operate the device without the

cover properly installed. There is no need for the operator to remove the cover.

DO NOT ATTEMPT TO OPERATE IF PROTECTION MAY BE

IMPAIRED

If the device appears damaged or operates abnormally, protection may be impaired. Do

not attempt to operate the device under these conditions. Refer all question of proper

device operation to qualified service personnel.

DO NOT ATTEMPT TO SERVICE UNLESS YOU ARE A FLUKE

QUALIFIED REPAIR TECHNICIAN

To avoid personal injury or death, remove the AC power cord and all analog and digital

connector modules before servicing the device.

Note

All signals must be removed from the analog and digital connector wiring

before opening the connector modules.

Table of Contents

Chapter Title Page

1 Introduction and Specifications........................................................ 1-1

Introduction ....................................................................................................... 1-3

Block Diagrams................................................................................................. 1-5

Specifications .................................................................................................... 1-7

2680A/2686A Combined Specifications....................................................... 1-7

2680A/2686A General Specifications............................................................... 1-8

Real-Time Clock and Calendar ......................................................................... 1-9

Trigger In Specifications................................................................................... 1-9

Trigger Out Specifications ................................................................................ 1-9

Master Alarm Output Specification................................................................... 1-10

Communication I/O........................................................................................... 1-10

2686A PC Card Storage .................................................................................... 1-10

Precision Analog Input (PAI) A/D Specifications............................................. 1-11

Specifications PAI A/D DC Voltage Measurement...................................... 1-11

PAI A/D AC Voltage Measurement Specifications...................................... 1-13

PAI A/D 4-Wire Resistance Measurement Specifications............................ 1-15

PAI A/D 2-Wire Resistance Measurement Specifications............................ 1-16

PAI A/D 4-Wire RTD per ITS-1990 Measurement Specifications .............. 1-16

PAI A/D 2-Wire RTD per ITS-1990 Measurement Specifications .............. 1-16

PAI A/D Thermocouple per ITS-1990 Measurement Specifications............ 1-17

PAI A/D Frequency Measurement Specifications ........................................ 1-20

Fast Analog Input (FAI) A/D Specifications..................................................... 1-21

FAI A/D DC Voltage Measurement Specifications...................................... 1-21

FAI A/D AC Voltage Measurement Specifications...................................... 1-22

FAI A/D 4-Wire Resistance Measurement Specifications............................ 1-24

FAI A/D 2-Wire Resistance Measurement Specifications............................ 1-25

FAI A/D 4-Wire RTD per ITS-1990 Measurement Specifications .............. 1-25

FAI A/D Thermocouple per ITS-1990 Measurement Specifications............ 1-26

FAI A/D Frequency Measurement Specifications ........................................ 1-28

Digital Input/Output Module............................................................................. 1-29

Digital Input/Output Specifications .............................................................. 1-29

Totalizer Input Specifications....................................................................... 1-30

Digital Relay Specifications.......................................................................... 1-30

Options and Accessories.................................................................................... 1-31

268XA

Service Manual

2 Theory of Operation........................................................................... 2-1

Introduction ....................................................................................................... 2-3

Main Power Supply....................................................................................... 2-5

Secondary Supplies....................................................................................... 2-5

Out-Guard Overview..................................................................................... 2-5

Microprocessor ......................................................................................... 2-6

FPGA........................................................................................................ 2-7

Other Bus Devices.................................................................................... 2-8

Serial Devices........................................................................................... 2-9

Trigger In/Out, Master Alarm................................................................... 2-9

PCMCIA Interface PCA (2686A-4041)............................................................ 2-10

Backplane PCA (268XA-4001)......................................................................... 2-10

Display Interface........................................................................................... 2-11

Module Interface........................................................................................... 2-11

Module Power Supply PCA (268XA-4031)...................................................... 2-11

Digital Input/Output PCA.................................................................................. 2-11

Microcontroller ............................................................................................. 2-12

Data Input Threshold..................................................................................... 2-12

Digital Input Buffers..................................................................................... 2-13

Digital Output Drivers................................................................................... 2-13

Relay Output Drivers .................................................................................... 2-13

Totalizer Input............................................................................................... 2-14

Totalizer Enable............................................................................................ 2-14

A/D Theory of Operations................................................................................. 2-14

A/D Converter PCA Block Description........................................................ 2-14

Analog Measurement Processor ............................................................... 2-15

Input Protection......................................................................................... 2-15

Input Signal Conditioning......................................................................... 2-15

Analog-to-Digital (a/d) Converter ............................................................ 2-15

Inguard Microcontroller............................................................................ 2-15

Channel Selection..................................................................................... 2-15

Open Thermocouple Check ...................................................................... 2-16

Analog Input PCA Block Description........................................................... 2-16

20-Channel Terminals............................................................................... 2-16

Reference Junction Temperature .............................................................. 2-16

A/D Converter PCA Circuit Description ...................................................... 2-16

Stallion Chip............................................................................................. 2-18

Input Protection......................................................................................... 2-18

Input Signal Conditioning......................................................................... 2-18

Function Relays ........................................................................................ 2-18

Channel Selection Circuitry...................................................................... 2-19

DC Volts and Thermocouples Measurement Circuitry............................. 2-19

Ohms and RTD Measurement Circuitry................................................... 2-20

AC Volts Measurement Circuitry............................................................. 2-22

Frequency Measurements ......................................................................... 2-23

Active Filter (ACV Filter) ........................................................................ 2-24

Voltage Reference Circuit ........................................................................ 2-24

Analog/Digital Converter Circuit ............................................................. 2-24

Autozero ................................................................................................... 2-24

Integrate.................................................................................................... 2-25

Deintegrate1.............................................................................................. 2-25

Deintegrate2.............................................................................................. 2-27

Overhead................................................................................................... 2-27

Inguard Digital Kernel Circuitry............................................................... 2-27

Contents

(continued)

iii

Open Thermocouple Detect Circuitry....................................................... 2-28

A4 Analog Input PCA Circuit Description................................................... 2-28

A31 A/D Power Supply Circuit Description................................................. 2-29

Controller/System Power (Outguard) to A3 A/D Converter (Inguard)

Communications ........................................................................................... 2-29

Special Codes................................................................................................ 2-29

Resets ............................................................................................................ 2-29

Commands..................................................................................................... 2-30

Perform Scan............................................................................................. 2-30

Perform Self-Test...................................................................................... 2-31

Return Firmware Version ......................................................................... 2-31

Return Boot Firmware Version................................................................. 2-31

Set Global Configuration.......................................................................... 2-32

Set Channel Configuration........................................................................ 2-32

Do Housekeeping...................................................................................... 2-32

Checksums .................................................................................................... 2-33

Errors............................................................................................................. 2-33

Power-Up Protocol........................................................................................ 2-33

Inguard Unresponsive ................................................................................... 2-33

Inguard Software Description ....................................................................... 2-33

Hardware Elements....................................................................................... 2-34

Channel MUX........................................................................................... 2-34

Function Relays ........................................................................................ 2-35

Stallion Chip and Signal Conditioning..................................................... 2-36

A/D ........................................................................................................... 2-39

DISCHARGE Signal ................................................................................ 2-42

Open-Thermocouple Detector .................................................................. 2-42

Channel Measurements................................................................................. 2-42

Reading Rates........................................................................................... 2-42

Measurement Types.................................................................................. 2-43

Autoranging.............................................................................................. 2-45

Overload ................................................................................................... 2-45

Housekeeping Readings................................................................................ 2-45

Reading Types .......................................................................................... 2-45

Housekeeping Schedule............................................................................ 2-46

Self-Tests....................................................................................................... 2-47

Power-Up Self-Tests................................................................................. 2-47

Self-Test Command.................................................................................. 2-47

3 Maintenance....................................................................................... 3-1

Introduction ....................................................................................................... 3-3

Self-Test Diagnostics and Error Codes ............................................................. 3-3

Cleaning............................................................................................................. 3-6

AC Fuse Replacement....................................................................................... 3-7

DC Fuse Replacement....................................................................................... 3-8

4 Performance Verification................................................................... 4-1

Introduction ....................................................................................................... 4-3

Configuring the Performance Test Setup...................................................... 4-3

Initializing the Performance Test Setup........................................................ 4-5

Accuracy Performance Tests............................................................................. 4-6

Master Alarm Output Tests........................................................................... 4-7

RS-232 Master Alarm Output Test........................................................... 4-7

Fluke DAQ Master Alarm Output Test .................................................... 4-7

268XA

Service Manual

Trigger Input Tests........................................................................................ 4-7

RS-232 Trigger Input Test........................................................................ 4-7

Fluke DAQ Trigger Input Test ................................................................. 4-8

Trigger Output Tests ..................................................................................... 4-8

RS-232 Trigger Output Test..................................................................... 4-8

Fluke DAQ Trigger Output Test............................................................... 4-8

Volts DC Accuracy Test (PAI Module)........................................................ 4-9

Volts DC Accuracy Test (FAI Module)........................................................ 4-10

Volts AC Accuracy Test ............................................................................... 4-11

Frequency Accuracy Test.............................................................................. 4-11

Analog Channel Integrity Test...................................................................... 4-12

Open Thermocouple Response Test.............................................................. 4-12

2-Wire Resistance Accuracy Test (PAI) - Optional...................................... 4-13

2-Wire Resistance Accuracy Test (FAI Module) - Optional ........................ 4-14

4-Wire Resistance Accuracy Test (PAI Module).......................................... 4-16

4-Wire Resistance Accuracy Test (FAI Module).......................................... 4-19

Digital Input/Output Tests............................................................................. 4-20

RS-232 Digital Input/Output Test............................................................. 4-20

Fluke DAQ Digital Input/Output Test...................................................... 4-21

DIO Relay/Fuse Tests................................................................................... 4-21

RS-232 DIO Relay Fuse Test ................................................................... 4-21

Fluke DAQ DIO Relay Fuse Test............................................................. 4-21

Totalizer Tests............................................................................................... 4-22

RS-232 Totalizer Count Test.................................................................... 4-22

RS-232 Totalizer Count and Enable Test ................................................. 4-22

RS-232 Totalizer Count and Direction Test ............................................. 4-22

RS-232 Totalizer Count and Debounce Test ............................................ 4-23

Fluke DAQ Totalizer Count Test.............................................................. 4-23

Fluke DAQ Totalizer Count and Enable Test........................................... 4-23

Fluke DAQ Totalizer Count and Direction Test....................................... 4-24

Fluke DAQ Totalizer Count and Debounce Test...................................... 4-24

5 Calibration.......................................................................................... 5-1

Introduction ....................................................................................................... 5-3

Calibration......................................................................................................... 5-3

Methods of Calibration...................................................................................... 5-3

Preparing for Calibration................................................................................... 5-3

Ending Calibration............................................................................................. 5-6

RS-232 Device Configuration Parameters ........................................................ 5-6

Manual Calibration Procedure........................................................................... 5-7

Manual Calibration Commands......................................................................... 5-9

V DC Calibration Procedure......................................................................... 5-10

V AC Calibration Procedure......................................................................... 5-12

Resistance Calibration Procedure.................................................................. 5-13

Frequency Calibration Procedure.................................................................. 5-15

6 Diagnostic Testing and Troubleshooting......................................... 6-1

Introduction ....................................................................................................... 6-3

Servicing Surface-Mount Assemblies............................................................... 6-3

Error Detection.................................................................................................. 6-4

FLASH ROM Parameter Defaults ................................................................ 6-7

Background Testing...................................................................................... 6-7

Retrieving Error Codes using RS-232........................................................... 6-8

Selecting the Diagnostic Tools.......................................................................... 6-8

Contents

(continued)

Diagnostic Tool dio....................................................................................... 6-8

Diagnostic Tool rELAy................................................................................. 6-9

Diagnostic Tool idS....................................................................................... 6-9

Diagnostic Tool conF.................................................................................... 6-10

Diagnostic Display Test................................................................................ 6-11

COMM Parameter Reset............................................................................... 6-11

Using the RS-232 Interface............................................................................... 6-11

Command Processing.................................................................................... 6-11

Device Configuration.................................................................................... 6-12

Command Set................................................................................................ 6-13

Troubleshooting the Device............................................................................... 6-25

General Troubleshooting............................................................................... 6-25

Sys/Ctrl PCA Troubleshooting...................................................................... 6-36

Troubleshooting the Sys/Ctrl PCA Digital Kernel ................................... 6-36

Troubleshooting the RS-232 Interface...................................................... 6-36

Troubleshooting the Ethernet Interface .................................................... 6-37

Troubleshooting the Keypad, Master Alarm Output, Trigger Input,

and Trigger Out Lines............................................................................... 6-37

Troubleshooting the Power Supply........................................................... 6-37

A2 Display PCA Troubleshooting ................................................................ 6-37

Variations in the Display .......................................................................... 6-39

PCMCIA PCA Troubleshooting ................................................................... 6-40

A/D Power Supply PCA Troubleshooting.................................................... 6-40

DIO Module Troubleshooting....................................................................... 6-40

Digital Input Buffers................................................................................. 6-41

Digital Output Drivers.............................................................................. 6-41

Relay Output Drivers................................................................................ 6-41

Totalizer Input........................................................................................... 6-42

Totalizer Enable........................................................................................ 6-42

Digital Output PCA Troubleshooting ........................................................... 6-42

A3 A/D Converter Module Troubleshooting................................................ 6-42

A3 Kernel.................................................................................................. 6-42

Break/Reset Circuit................................................................................... 6-43

Out of Tolerance Readings ....................................................................... 6-43

Troubleshooting Relay Problems.............................................................. 6-44

A4 Analog Input PCA Troubleshooting........................................................ 6-44

Troubleshooting Calibration Failures................................................................ 6-44

Retrieving Calibration Constants.................................................................. 6-45

FlukeDAQ Software.......................................................................................... 6-47

7 Replaceable Parts.............................................................................. 7-1

Introduction ....................................................................................................... 7-3

How to Obtain Parts .......................................................................................... 7-3

Service Centers.................................................................................................. 7-3

Parts Lists .......................................................................................................... 7-4

8 Schematics......................................................................................... 8-1

Introduction ....................................................................................................... 8-3

268XA

Service Manual

vii

List of Tables

Table Title Page

1-1. 268XA General Specifications .............................................................................. 1-8

1-2. 268X Real-Time Clock and Calendar.................................................................... 1-9

1-3. Trigger In Specification......................................................................................... 1-9

1-4. Trigger Out Specification ...................................................................................... 1-9

1-5. Master Alarm Output Specification....................................................................... 1-10

1-6. 2686A - Active Channels and Number of Scans to Card Capacity....................... 1-10

1-7. PAI A/D DC Voltage General Specifications........................................................ 1-11

1-8. PAI A/D DC Voltage Range and Resolution Specifications................................. 1-12

1-9. PAI A/D DC Voltage Accuracy Specifications..................................................... 1-12

1-10. PAI A/D AC Voltage General Specifications........................................................ 1-13

1-11. PAI A/D AC Voltage Range and Resolution Specifications................................. 1-13

1-12. PAI A/D AC Voltage Accuracy Specifications..................................................... 1-14

1-13. PAI A/D 4-Wire Resistance Temperature Coefficient .......................................... 1-15

1-14. PAI A/D 4-Wire Resistance Range and Resolution Specifications....................... 1-15

1-15. PAI A/D 4-Wire Resistance Accuracy Specifications........................................... 1-15

1-16. PAI A/D 4-Wire RTD Temperature Coefficient.................................................... 1-16

1-17. PAI A/D 4-Wire RTD Specifications.................................................................... 1-16

1-18. PAI A/D Thermocouple General Specifications.................................................... 1-17

1-19. PAI A/D Thermocouple Specifications................................................................. 1-18

1-20. PAI A/D Frequency Accuracy Specifications ....................................................... 1-20

1-21. PAI A/D Frequency Sensitivity Specifications...................................................... 1-20

1-22. FAI A/D DC Voltage General Specifications........................................................ 1-21

1-23. FAI A/D DC Voltage Resolution and Repeatability Specifications...................... 1-21

1-24. FAI A/D DC Voltage Accuracy Specifications..................................................... 1-22

1-25. FAI A/D AC Voltage General Specifications........................................................ 1-22

1-26. FAI A/D AC Voltage Range and Resolution Specifications................................. 1-23

1-27. FAI A/D AC Voltage Accuracy Specifications..................................................... 1-23

1-28. FAI A/D 4-Wire Resistance Temperature Coefficient .......................................... 1-24

1-29. FAI A/D 4r-Wire Resistance Range and Resolution Specifications...................... 1-24

1-30. FAI A/D 4-Wire Resistance Accuracy Specifications........................................... 1-24

1-31. FAI A/D 4-Wire RTD Temperature Coefficient.................................................... 1-25

1-32. FAI A/D 4-Wire RTD Specifications.................................................................... 1-25

1-33. FAI A/D Thermocouple General Specifications.................................................... 1-26

1-35. FAI A/D Frequency Accuracy Specifications ....................................................... 1-28

1-36. FAI A/D Frequency Sensitivity Specifications...................................................... 1-28

268XA

Service Manual

viii

1-37. DIGITAL I/O Specification................................................................................... 1-29

1-38. Totalizer Specification........................................................................................... 1-30

1-39. DIGITAL I/O Relay Specification......................................................................... 1-30

1-40. Models, Options and Accessories.......................................................................... 1-31

2-1. Contoller Connector Description........................................................................... 2-4

2-2. Backplane Connector Description ......................................................................... 2-10

2-3. Range of Buffer Amplifier..................................................................................... 2-19

2-4. Measurement Matrix for DC Volts........................................................................ 2-20

2-5. Measurement Matrix for Ohms.............................................................................. 2-21

2-6. Measurement Matrix for AC Volts........................................................................ 2-22

2-7. Analog/Digital Converter Measurement Cycle...................................................... 2-25

2-8. Tree Bits................................................................................................................. 2-34

2-9. Channel Bits........................................................................................................... 2-35

2-10. Tree and Channel Switch Settling Times............................................................... 2-35

2-11. Function Relays ..................................................................................................... 2-36

2-12. Function Relay Settling Time................................................................................ 2-36

2-13. Stallion Switch Settings......................................................................................... 2-37

2-14. Signal Conditioning Settling Time ........................................................................ 2-38

2-15. A/D Command Codes............................................................................................ 2-40

2-16. A/D Readings to Average to Obtain a Measurement............................................. 2-42

2-17. Frequency Sensitivity............................................................................................. 2-44

2-18. A/D Reading to Average to Obtain a Reference Balance Measurement ............... 2-46

3-1. Self-Test Codes...................................................................................................... 3-4

4-1. Recommended Test Equipment............................................................................. 4-4

5-1. RS-232 Device Configuration for Calibration Procedures.................................... 5-6

5-2. Calibration Commands .......................................................................................... 5-9

5-3. Manual Calibration Command Responses............................................................. 5-10

5-4. Manual V dc Calibration........................................................................................ 5-11

5-5. Manual V ac Calibration........................................................................................ 5-13

5-6. Manual Resistance Calibration.............................................................................. 5-15

5-7. Manual Frequency Calibration .............................................................................. 5-15

6-1. Self-Test Error Codes ............................................................................................ 6-5

6-2. FLASH ROM Parameter Defaults......................................................................... 6-7

6-3. Corrective Action for Background Error Checking............................................... 6-7

6-4. Device Firmware Descriptions .............................................................................. 6-10

6-5. Device Default COMM Parameters....................................................................... 6-11

6-6. Device Configuration............................................................................................. 6-13

6-7. RS-232 Command Set............................................................................................ 6-14

6-8. Range Settings ....................................................................................................... 6-20

6-9. Relating Selftest Errors to Device Problems.......................................................... 6-26

6-10. Hints for Troubleshooting...................................................................................... 6-35

6-11. A2 Display PCA Initialization Routines................................................................ 6-38

6-12. A3 A/D Converter PCA Jumper Positions............................................................. 6-43

6-13. A/D Module Calibration Constants ....................................................................... 6-46

List of Figures

Figure Title Page

1-1. 2680A/2685A Device ............................................................................................ 1-4

1-2. 268XA Chassis ...................................................................................................... 1-5

2-1. Communication Control System............................................................................ 2-3

2-2. 268XA Main Supply Circuit.................................................................................. 2-4

2-3. System Interface Unit ............................................................................................ 2-6

2-4. FPGA Block Diagram............................................................................................ 2-8

2-5. A3 A/D Converter Block Diagram ........................................................................ 2-17

2-6. DC Volts 300 V Range Simplified Schematic....................................................... 2-20

2-7. RTD Measurement Simplified Schematic............................................................. 2-21

2-8. AC Volts #V Range Simplified Schematic............................................................ 2-23

2-9. Integrator Output Waveform for Input Near 0....................................................... 2-26

2-10. Integrator Output Wavefrom for Input Near + Full Scale ..................................... 2-26

2-11. Integrator Output Waveform for Input Near - Full Scale ...................................... 2-27

2-12. A/D Timing (FAI Normal Reading)...................................................................... 2-39

2-13. A/D Timing (PAI Normal Reading, PAI and FAI Reference Balance)................. 2-39

2-14. A/D Status Signals................................................................................................. 2-40

3-1. Replacing the Fuse................................................................................................. 3-7

3-2. DC Fuse Location.................................................................................................. 3-9

4-1. Connection Between Device and Host .................................................................. 4-5

4-2. 2-Wire Connections to 5700A............................................................................... 4-15

4-3. 4-Wire Connections to the Universal Input Module (Resistor)............................. 4-16

4-4. 4-Wire Connections to the Universal Input Module (5700A) ............................... 4-17

4-5. DIO Connector Module ......................................................................................... 4-20

5-1. Device and Host Computer Calibration Setup....................................................... 5-5

5-2. Universal Input Module Calibration Connections................................................. 5-5

5-3. Two-Wire Calibration Connection ........................................................................ 5-6

5-4. Four-Wire Calibration Connection........................................................................ 5-7

6-1. Display Test Pattern #1.......................................................................................... 6-38

6-2. Display Test Pattern #2.......................................................................................... 6-38

7-1. 268XA Final Assembly.......................................................................................... 7-10

7-2. Blank Module ........................................................................................................ 7-11

7-3. DIO Module........................................................................................................... 7-13

7-4. FAI Module............................................................................................................ 7-15

7-5. PAI Module............................................................................................................ 7-17

7-6. Isothermal Input..................................................................................................... 7-18

268XA

Service Manual

8-1. Backplane PCA...................................................................................................... 8-3

8-2. Controller/System Power PCA.............................................................................. 8-5

8-3. Digital I/O PCA ..................................................................................................... 8-11

8-4. Backplane Extender PCA ...................................................................................... 8-15

8-5. Extender PCA........................................................................................................ 8-17

8-6. A/D Supply Assembly ........................................................................................... 8-19

8-7. PCMCIA PCA ....................................................................................................... 8-21

8-8. Output PCA............................................................................................................ 8-23

8-9. A/D (PFE) PCA..................................................................................................... 8-25

8-10. A/D (FFE) PCA ..................................................................................................... 8-32

8-11. Analog Input Connector PCA................................................................................ 8-39

8-12. Display PCA .......................................................................................................... 8-41

1-1

Chapter 1

Introduction and Specifications

Title Page