Keithley 6521, Instruction Manual, Page: 33 / 65

Operation
3-5
4. Set the settling time as desired, then press ENTER.
5. Press EXIT to return to normal display.
3.4.5 Scanning procedure
NOTE
Before scanning, you should configure the
card as covered in paragraph 3.4.4.
1. Press the CARD key, and note that the instrument dis-
plays the following:
SCANNER OPTION
CHANNEL-CLOSURES PERFORM-SCAN
2. Select PERFORM-SCAN, then press ENTER. The
Model 6517 will prompt you as to the type of scan:
CHOOSE SCAN TYPE
EXTERNAL INTERNAL
3. Select INTERNAL, then press ENTER. You will then be
prompted to set the scan count (number of scans):
SCAN COUNT = 00010
4. Set the scan count to the desired value, then press the
ENTER key. The instrument will then prompt you as to
whether or not you wish to use the scan timer:
USE SCAN TIMER?
YES NO
5. If you wish to use the timer to control the length of the
scan, select YES; otherwise choose NO, then press
ENTER.
6. If you are using the scan timer, the unit will prompt you
for the scan interval (length of scan):
INTRVL = 00002.500
7. Set the scan interval to the desired value, then press EN-
TER. The instrument will then display the following
asking whether or not you intend to store measurement
data in memory:
DATA TO MEMORY?
YES NO
8. If you desire to store measurement data in the Model
6517 buffer, select YES; otherwise choose no, then press
ENTER.
9. Assuming that you chose to store readings in the buffer,
the instrument will display the following:
00100 RDGS TO BUFFER
Press ENTER to continue
10. Press ENTER to continue, and the unit will display one
last prompt before starting the scan:
Press ENTER to begin
11. Press the ENTER key to start scanning. During scan-
ning, the unit will display the current reading being pro-
cessed. For example:
Storing reading 010 of 100
NOTE
To abort scanning at any time, press the
EXIT key. The unit will then display the
following message to indicate that scan-
ning has been aborted:
SCANNING DISABLED
12. After the scan process has completed normally, the in-
strument will display the following:
SCAN COMPLETE
RECALL-DATA SCAN-AGAIN EXIT
13. Choose the desired option as follows:
RECALL-DATA: Choose this option if you wish to re-
call data stored in the buffer. Use the range keys to scroll
through readings.
SCAN-AGAIN: Select this option to scan again.
EXIT: Choose this option to exit scanning and return to
normal operation.
3.5 IEEE-488 bus operation
The following paragraphs summarize bus scanner com-
mands and also cover such aspects as closing and opening
channels, card configuration, and scanning ver the bus.
3.5.1 IEEE-488 bus scanner commands
Table 3-3 summarizes commands that control basic scanning
operations over the IEEE-488 bus. For information on other
bus commands, refer to the Model 6517 Electrometer User’s
Manual.