Keithley 7013-C, Instruction Manual

Page: 50 / 71

Service Information
5-7
5.3.7 Channel to channel isolation tests
These tests check the leakage resistance (isolation)
between adjacent channels. A channel is simply the
high (H) and low (L) circuit from the input (IN) to the
output (OUT) that results by closing the channel relay.
In general, the test is performed by applying a voltage
(+100V) across two adjacent channels and then mea-
suring the leakage current across the channels. The iso-
lation resistance is then calculated as R = V/I. In the
following procedure, the Model 617 functions as both a
voltage source and an ammeter. In the V/I function,
the Model 617 internally calculates the resistance from
the known voltage and current levels and displays the
resistance value.
Refer to Figure 5-4 and perform the following steps to
test channel to channel isolation:
1. Turn the Model 7001 off if it is on.
2. Jumper input (IN) high (H) to input (IN) low (L)
for Channels 1 and 2 as shown in Figure 5-4.
3. Connect the Model 617 to Channels 1 and 2 as
shown in the illustration. Make sure the voltage
source is in standby.
4. Install the Model 7013 in slot 1 (CARD 1) of the
Model 7001 if it is not already installed.
KEITHLEY 182 SENSITIVE DIGITAL VOLTMETER
TRG
SRQ
REM
TALK
LSTN
Model 182
Each channel :
7013
IN
OUT
H
L
H
L
HI
LO
Low thermal short;
clean, high purity
copper
Model 1484
Low Thermal Cable
(Unterminated)
Figure 5-3
Contact potential testing
WARNING
The following steps use high voltage
(100V). Be sure to remove power
from the circuit before making con-
nection changes.
5. On the Model 617, select the 2pA range, and enable
zero check and zero correct in that order. Leave
zero correct enabled for the entire procedure.
6. On the Model 617, select the 20pA range and
release zero check.
7. On the Model 617, press suppress to cancel offset
current and then enable zero check.
8. On the Model 617, set the voltage source for +100V,
and select the 20nA current range. Make sure the
voltage source is in standby.
9. Place the Model 617 in the V/I measurement func-
tion by pressing SHIFT OHMS.
10. Turn on the Model 7001, and program it to close
Channels 1!1 and 1!2 (Channels 1 and 2).
11. On the Model 617, disable zero check and press
OPERATE to 100V.
12. After allowing the reading on the Model 617 to set-
tle, verify that it is >10G
Ω
. This measurement is the
channel to channel leakage resistance (isolation)
between Channels 1 and 2.
13. Place the Model 617 in standby and enable zero
check.
14. Turn off the Model 7001.