09-30-2009 05:08 AM
Hey,
ich have a problem with my Keithley 2000 by measurements over RS232.
My programm is running, its a simple serial read and write VI. I send him an command to measure and nothing is happening. I got nothing back....
I add the VI and the commands, maybe somebody knows whats wrong with my VI!
Thanks a lot
Greetings
Ralf
09-30-2009 05:53 AM
I have no time to look into your code, but most likley you miss the termination char. On a string constant you can switch to \-display and then use \n or \n\r depending on the settings. You can also look into the LV drivers for the keithley 2000, they are available on ni.com and/or on keithley.com
Felix
09-30-2009 06:15 AM
thanks for your help.
know i get the error: timeout expired before operation completed. whats the reason for that error?
09-30-2009 06:29 AM
I guess that is comming from the read. Does it return any data?
There is a VISA property node for the timeout, so you might increase it. If you use the serial port open vi (I don't heve the name correctly), there is also a timeout to specify.
Felix
09-30-2009 06:34 AM
yes its caused from the read function...
if i increase the timeout its still not working, i think the read does not work because its not able to get data back. the question is why does the read not work?
09-30-2009 06:46 AM
I just took a look on some old code of mine. After writing READ\n I wait 100 ms. Then I use the Property Bytes.At.Port for the read function. Generally using some waits helps when programming RS232.
Felix
09-30-2009 06:48 AM
09-30-2009 07:02 AM
im using a wait function, thats all running...
i think something with my writing is not correct....i send the command
:READ\n;
nothing is comming back, the keithley 2000 is working with SCPI commands, i tried to use them but its not working...
whats the correct syntax, maybe i messed something up....?
thanks for your help felix
09-30-2009 07:06 AM
09-30-2009 07:11 AM
okay dennis, i know what you mean, i tried to do this, but whats the correct syntax?
*IDN?
:MEAS:VOLT:DC