Keithley 7999-2, Instruction Manual

Page: 32 / 44

Service Information 4-5
Contact potential tests
Perform the following procedure to check contact potential of each relay contact:
1. Connect the low-thermal cable to the Model 2182 Nanovoltmeter INPUT jack.
2. Turn on the Model 2182, and allow the unit to warm up for one hour to achieve rated
accuracy.
3. Select the Model 2182 10mV range.
4. Temporarily short the Channel 1 HI and LO leads of the low-thermal cable.
5. Enable REL on the Model 2182.
6. Connect the Model 2182 to the relay contact being tested, as shown in Figure 4-2. Be
sure to make connections to the Channel 1 input terminals, and use that channel for
measurements.
7. Close the relay being tested.
8. Verify that the Model 2182 reading is <10
µ
V.
9. Open the relay being tested.
10. Repeat steps 6 through 9 for all relays on the card.
2182 NANOVOLTMETER
RANGE
CHANNEL 1
SHIFT
LOCAL
POWER
RANGE
SHIFT
CH1 REM
TALK
LSTN
SRQ
STAT REL FILT
4W
BUFFER
MATH
REAR SCAN
TIMER
STEP CH2 CH3 CH4 CH5 CH6 CH7 CH8 CH9 CH10
HOLD TRIG FAST MED SLOW AUTO ERR
AUTO
HI LO
CHANNEL 2
HI
120V MAX
12V MAX
L
SYNC
CAT I
350V PEAK ANY
TERMINAL TO CHASSIS
!
LO
EXIT ENTER DIGITS RATE
ON/OFF VALUE TRIG EX TRIG STORE RECALL
DCV1 V1 / V2
MX+B
% V
1
-V
2
DCV2 ACAL FILT REL
TEMP
1
TEMP
2
TYPE A OUT TCOUPL
DELAY HOLD
RS232 GPIB
STEP SCAN
CAL TEST
OUTPUT
SAVE RESTR
CONFIG HALT
BUFFER
SETUP
LIMITS
Model 2182 Nonovoltmeter
In
Out
H
L
G
Close
Relay
Model 7999-2 Relay
Under Test. See Section 2
for Detailed Connections.
Low Thermal Cable
Connect to and
use Channel 1
Figure 4-2
Contact potential
connections