Channel Resistance Tests - Keithley 7021 Instruction Manual

WARNING
When wiring a connector and device
under test, do not leave any exposed
wires or connections. No conductive
part of the circuit may be exposed. Prop-
erly cover the conductive parts, or death
by electric shock may occur.
CAUTION
After making solder connections to a
connector, remove solder flux as ex-
plained in the Handling and cleaning
precautions paragraph. Failure to clean
the solder connections could result in
degraded performance and prevent the
card from passing verification tests.
Before pre-wiring any connectors or plugs, study the follow-
ing test procedures to fully understand the connection re-
quirements.

Channel resistance tests

Referring to Figure 6-1, perform the following steps to verify
that each contact of every relay is closing properly and that
the resistance is within specification.
1. Turn off the Model 7001/7002 if it is on.
2. Turn on the Model 2000 and allow it to warm up for one
hour before making measurements.
3. Connect all input terminals of bank A together to form
one common terminal, as shown in Figure 6-1.
Model 2000
(Measure 4-Wire Ohms)
POWER
Input Ω 4 Wire LO
1 2
A
3 4
B
H L H L H
Note: Connections are set
up to test Bank A HI.
Figure 6-1
Path resistance test connections
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Input Ω 4 Wire HI
Input HI
HI
Input LO
LO
Jumpers
6 7 11 12 16 17 21
5 8 9 10 13 14 15
L H L H L H L H L H L H
Bank Inputs
Model 7021
4. Set the Model 2000 to the 100 Ω range and connect the
four test leads to the INPUT and INPUT Ω 4 WIRE
jacks.
5. Short the four test leads together and zero the Model
2000. Leave zero enabled for the entire test.
6. Connect INPUT HI and INPUT Ω 4 WIRE HI of the
Model 2000 to the common terminal (jumper on bank A
inputs). It is recommended that the physical connections
be made at the inputs of bank A, as shown in Figure 6-1.
7. Connect INPUT LO and INPUT Ω 4 WIRE LO to the
HI (H) terminal of bank A.
8. Install the Model 7021 in slot 1 (CARD 1) of the Model
7001/7002.
9. Turn on the Model 7001/7002 and program it to close
channel 1!1 (bank A, input 1). Verify that the resistance
of this path is <1.25 Ω .
10. Open channel 1!1 and close channel 1!2 (bank A, input
2). Verify that the resistance of this path is <1.25 Ω .
11. Using the basic procedure in steps 9 and 10, check the
resistance of bank A HI (H) terminal paths for the rest of
the bank A inputs (channels 1!6, 1!7, 1!11, 1!12, 1!16,
1!17, 1!21, 1!22, 1!26, and 1!27).
12. Turn off the Model 7001/7002 and move the INPUT LO
and INPUT Ω 4 WIRE LO test leads to the LO (L) ter-
minal of bank A.
13. Repeat steps 9 through 11 to check the LO (L) terminal
paths of bank A (channels 1!1, 1!2, 1!6, 1!7, 1!11, 1!12,
1!16, 1!17, 1!21, 1!22, 1!26, and 1!27).
14. Repeat the basic procedure in steps 1 through 13 for
bank B (channels 1!3-1!5, 1!8-1!10, 1!13-1!15, 1!18-
1!20, 1!23-1!25, and 1!28-1!30).
22 26 27
H
L
18 19 20 23 24 25
L H L H L H L H L H L H
Service Information
Bank
Outputs
28 29 30
H
L
L H L H L H L
6-3