Lakeshore Learning Materials 642 - Manual (Page 72)

Lake Shore Model 642 Electromagnet Power Supply User’s Manual
5-20 Computer Interface Operation
5.1.5.3 Program Operation
Once the running, try the following commands and observe the response of the instrument. Input from the user is shown
in bold and terminators are added by the program. The word [term] indicates the required terminators included with the
response.
ENTER COMMAND? *IDN?
Identification query. Instrument will return a string identifying itself.
RESPONSE: LSCI,MODELModel 642,1234567,06122006[term]
ENTER COMMAND? SETI?
Output current setting query. Instrument will return a string with the
present output current setting.
RESPONSE: +20.0545[term]
ENTER COMMAND? XPGM 0
External program mode command. Instrument will set program mode
to internal. No response will be sent.
ENTER COMMAND? XPGM?
External program mode query. Instrument will return a string with the
present external program mode setting.
RESPONSE: 0[term]
ENTER COMMAND? XPGM 1;XPGM?
External program mode command followed by a query. Instrument will
change to external programming mode, then return a string
RESPONSE: 1[term]
with the present setting.
The following are additional notes on using either IEEE-488 Interface program.
• If you enter a correctly spelled query without a “?,” nothing will be returned. Incorrectly spelled commands and
queries are ignored. Commands and queries should have a space separating the command and associated parameters.
• Leading zeros and zeros following a decimal point are not needed in a command string, but are sent in response to a
query. A leading “+” is not required but a leading “–” is required.
5.1.6 Troubleshooting
New Installation
1. Check instrument address.
2. Always send terminators.
3. Send entire message string at one time including terminators.
4. Send only one simple command at a time until communication is established.
5. Be sure to spell commands correctly and use proper syntax.
6. Attempt both ‘Talk’ and ‘Listen’ functions. If one works but not the other, the hardware connection is working, so
look at syntax, terminators, and command format.
7. If only one message is received after resetting the interface, check the “repeat addressing” setting. It should be
enabled.
Old Installation No Longer Working
8. Power instrument off then on again to see if it is a soft failure.
9. Power computer off then on again to see if the IEEE-488 card is locked up.
10. Verify that the address has not been changed on the instrument during a memory reset.
11. Check all cable connections.
Intermittent Lockups
12. Check cable connections and length.
13. Increase delay between all commands to 50 ms to make sure instrument is not being over loaded.