
Lake Shore Model 340 Temperature Controller User’s Manual
9-20
Remote Operation
9.2.7.3 Program
Operation
Once either example program is 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,MODEL340,123456,02032001[term]
ENTER COMMAND? KRDG? A
Query Kelvin Reading for Input A. Controller returns temperature
reading in kelvin.
+077.350E+0
ENTER COMMAND? HTR?
Query Heater Output. Controller returns heater output in percent.
+050.0%
ENTER COMMAND? CMODE 1,1
Set Control Loop 1 to Manual PID.
ENTER COMMAND? PID? 1
Query Current PID Status. Controller returns separate PID
settings.
0020.0, 0010.0, 0005.0
ENTER COMMAND? PID 1,25,15,6
Set Loop 1 PID values to 25, 15, and 6.
ENTER COMMAND? BEEP 1;BEEP?
Combination command of setting the system beeper on and then
requesting the system beeper status.
1
ENTER COMMAND?
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.
9.2.8 Troubleshooting
New Installation
1. Check instrument Baud rate.
2. Make sure transmit (TD) signal line from the instrument is routed to receive (RD) on the computer and
vice versa. (Use a null modem adapter if not).
3. Always
send
terminators.
4. Send entire message string at one time including terminators (many terminal emulation programs do not).
5. Send only one simple command at a time until communication is established.
6. Be sure to spell commands correctly and use proper syntax.
Old Installation No Longer Working
7. Power instrument off then on again to see if it is a soft failure.
8. Power computer off then on again to see if communication port is locked up.
9. Verify that Baud rate has not been changed on the instrument during a memory reset.
10. Check all cable connections.
Intermittent Lockups
11. Check cable connections and length.
12. Increase delay between all commands to 100 ms to make sure instrument is not being over loaded.