Service Information
5-10
5.3.8 Differential isolation tests
These tests check the differential isolation (leakage
resistance) between high (H) and low (L) of every
channel.
In general, the test is performed by applying a voltage
(100V) across the terminals and then measuring the
leakage current. The isolation resistance is then calcu-
lated as R = V/I. In the following procedure, the Model
617 functions as a voltage source and an ammeter. In
the V/I function, the Model 617 internally calculates
the resistance from the known voltage and current lev-
els and displays the resistance value.
Refer to Figure 5-5 and perform the following steps to
test differential isolation.
1. Turn the Model 7001 off if it is on.
2. Connect the Model 617 to Channel 1 as shown in
Figure 5-5. Make sure the voltage source is in
standby.
3. Install the Model 7013 in slot 1 (CARD 1) of the
Model 7001 if it is not already installed.
WARNING
The following steps use high voltage
(100V). Be sure to remove power
from the circuit before making con-
nection changes.
4. 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.
5. On the Model 617, set the voltage source for +100V,
and select the 20nA current range. Make sure the
voltage source is still in standby.
6. Place the Model 617 in the V/I measurement func-
tion by pressing SHIFT OHMS.
7. Turn on the Model 7001 and program the Model
7001 to close Channel 1!1 (Slot 1, Channel 1).
8. On the Model 617, disable zero check and press
OPERATE to 100V.
9. After allowing the reading on the Model 617 to set-
tle, verify that it is >10G
Ω
. This measurement
checks the differential isolation of Channel 1.
10. Enable zero check on the Model 617 and place its
voltage source in standby.
11. Repeat the basic procedure in steps 1 through 10 to
check differential isolation of the other channels of
the Model 7013. Remember to close the relay of the
channel being checked.
12. Place the Model 617 in standby and turn the Model
7001 off.
HI
Model 617
INPUT
Model 7025
Unterminated
Triax Cable
(Red)
Banana to Banana Cable
Ground Link
Removed
Unterminated
Banana Cable
Source V and
Measure V/I
HI
Each channel :
7013
IN
OUT
H
L
H
L
Figure 5-5
Differential isolation testing
Summary of Contents for 7013-C
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