Keithley 6521, Инструкция по эксплуатации, Страница: 47 / 65

Service Information
4-5
5. With the power off, install the scanner card in the Model
6517 Electrometer OPTION SLOT.
6. Turn on the Model 6517 power.
7. Press CONFIG then CARD, and program the Model
6517 for the current scan mode. (See paragraph 3.4.4 for
details.)
8. Press the OPTION CARD button, then select OPEN-
ALL-CHANNELS in the CHANNEL SELECTION
menu to make certain that all channels are open.
9. Connect the DMM to the HI and LO terminals of the
channel 1 input jack, as shown in Figure 4-3.
10. Note the resistance reading on the DMM. Verify that the
reading is <1 Ω .
11. Repeat steps 9 and 10 for channels 2-10. Be sure to con-
nect the DMM to the HI and LO input terminals of the
channel being tested. Also, the channel being tested
must be open so that the ground relay is closed.
Figure 4-3
Connections for ground relay contact resistance tests
EXIT ENTER
FILTER MATH
CONFIG MENU
STORE RECALL
CHAN SCAN
REL TRIG
INFO LOCAL
DCV ACV DCI ACI Ω 2 Ω 4 FREQ TEMP
2001 MULTIMETER
RANGE
!
F
500V
PEAK
FRONT/REAR
2A 250V
AMPS
HI
INPUT
LO
SENSE
Ω 4 WIRE
INPUTS
350V
PEAK
1100V
PEAK
AUTO
PREV
NEXT
DISPLAY
POWER
RANGE R
CAL
1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
EDIT ERR REM TALK LSTN SRQ REAR REL FILT MATH 4W AUTO ARM TRIG SMPL
Note: Model 6521 shown. Model
6522 connections same except
for triax inputs.
H
Out
G
H
L
IN 1
H
L
IN 10
IN 2....9
L
Model 6521/22 Card
Channel 1 connection shown
Input HI
Input LO
Model 2001 DMM
4.3.6 Ground relay contact resistance tests
Perform the following steps to verify that the contact resis-
tance of the ground relay for each channel is within specifie
limits.
1. Connect an alligator clip lead to the HI and LO input
jacks of the DMM to be used for the test. (See Figure
4-3.)
2. Turn on the DMM, and allow it to warm up for one hour
before making the tests.
3. Select the ohms function and the 20 Ω range on the
DMM.
4. Temporarily short the ends of the DMM leads together,
then enable the DMM REL mode to null out any resid-
ual test lead resistance. Leave REL enabled for the re-
mainder of the contact resistance tests.