Keithley 7021 Instruction Manual page 11

Measurement considerations............................................................................................................................. 5-13
Path isolation............................................................................................................................................. 5-13
Magnetic fields.......................................................................................................................................... 5-14
Radio frequency interference .................................................................................................................... 5-14
Ground loops............................................................................................................................................. 5-14
Keeping connectors clean ......................................................................................................................... 5-15
AC frequency response ............................................................................................................................. 5-15
6 Service Information
Introduction ......................................................................................................................................................... 6-1
Handling and cleaning precautions ..................................................................................................................... 6-1
Performance verification..................................................................................................................................... 6-2
Environmental conditions ........................................................................................................................... 6-2
Recommended equipment........................................................................................................................... 6-2
Multiplexer connections.............................................................................................................................. 6-2
Channel resistance tests .............................................................................................................................. 6-3
Offset current tests ...................................................................................................................................... 6-4
Contact potential tests ................................................................................................................................. 6-6
Bank and channel-to-channel isolation tests ............................................................................................... 6-7
Differential and common-mode isolation tests ......................................................................................... 6-11
Channel functionality test ................................................................................................................................. 6-13
Special handling of static-sensitive devices...................................................................................................... 6-13
Principles of operation ...................................................................................................................................... 6-14
Block diagram ........................................................................................................................................... 6-14
ID data circuits .......................................................................................................................................... 6-15
Multiplexer relay control .......................................................................................................................... 6-15
Multiplexer relay power control................................................................................................................ 6-16
Digital I/O output channel control ............................................................................................................ 6-16
Digital I/O input channel control .............................................................................................................. 6-16
Power-on safeguard................................................................................................................................... 6-16
Troubleshooting ................................................................................................................................................ 6-17
Troubleshooting equipment ...................................................................................................................... 6-17
Troubleshooting access ............................................................................................................................. 6-17
Troubleshooting procedure ....................................................................................................................... 6-18
7 Replaceable Parts
Introduction ......................................................................................................................................................... 7-1
Parts lists .............................................................................................................................................................. 7-1
Ordering information .......................................................................................................................................... 7-1
Factory service .................................................................................................................................................... 7-1
Component layouts and schematic diagrams ...................................................................................................... 7-1
Index
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