Keithley 6521, Instruction Manual, Page: 32 / 65

Operation
3-4
3.4.4 Card configuration
Selecting scan list channels
To choose the channels to include in the scan list, perform
the following steps:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the in-
strument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select CHANNELS, then press ENTER, and note that
the instrument displays the following:
CONFIGURE CHANNELS
INTERNAL-CHANS EXTERNAL-INPUTS
4. Select INTERNAL-CHANS, then press ENTER. The
following will then be displayed:
SET INTERNAL CHANS
1=ON 2=ON 3=ON 4=ON 5=ON
6=ON 7=ON 8=ON 9=ON 10=ON
5. Using the range and cursor keys, select the channels you
wish to include in the scan list. (ON = include channel;
OFF = exclude channel.)
6. Press the ENTER key to complete programming, then
press EXIT twice to return to normal display.
Scan mode
The scanner card can be configured for either voltage or cur-
rent operation. When in the voltage mode, the card is config
ured for break-before-make operation. (The relay for the
presently closed channel opens before the next channel relay
closes.) When in the current mode, the HI and LO terminals
of each input channel remain shorted together when the
channels are open.
Program the scan mode as follows:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the in-
strument displays the following message:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select SCAN-MODE, then press ENTER. The instru-
ment will display the following:
SCAN MODE
VOLTAGE CURRENT
4. Select VOLTAGE or CURRENT as desired, then press
ENTER.
5. Press EXIT twice to return to normal display.
Setting the voltage source limit
The maximum recommended voltage for the Model 6522
card is 200V, while the Model 6521 is limited to 30V for
safety reasons. Use the following procedure to program the
voltage limit up to a maximum of 200V.
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the in-
strument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select VSRC-LIMIT, then press ENTER. The instru-
ment will display the following:
LIMIT VSRC TO 200V
YES NO
4. To limit the voltage source to 200V, select YES, then
press ENTER.
5. Press EXIT twice to return to normal display.
Settling time
The setting time parameter allows you to program a delay
time to allow circuit settling. The settling time between chan-
nels can be set to any value in the range of 0sec to
999.999sec. Program the settling time as follows:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the in-
strument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select SETTLING-TIME, then press ENTER, and note
that the instrument displays the following:
SETTLE-t: 000.000sec