08-20-2010 01:03 PM
Hi,
I have written a VI to send voltage signal and read back the channel 1 and channel 2 data of a SR830 lockin amplifier using serial port. I obtain the channel readings as a single string separated by "," using the snap function. The problem is that when ever the channel 2 data gets very close to zero then the output is in engineering format like say 6.73883e-005. This is where the problem occurs. When such a situation is encountered, I always get a time out error. I have tried to increase the byte count in the read VISA ( till around 50) but then I get this error more often, but if I reduce it to something like 17, I only get this error as I mentioned above only when the channel 2 reading is very nearly zero. I have tried to reduce the byte (to as low as 8), but then I donot get back the whole channel 2 reading (this ch2 reading is also important to me). I am in a fix. Please give me a way out.
I am attaching here the VIs.
08-20-2010 01:30 PM
As your signal approaches 0 it takes longer for the readings to take place (the nature of a Lock-in amp) you may want to increase the VISA timeout or wait for another event (like a SRQ) that will tell you when new data is ready
08-26-2010 12:11 PM
I am really sorry for the late reply. Well, I tried to increase the time constant inthe sr830 initialize VI, upto 240,000 ms. But I still get the error, and not always now when the reading is near zero. Can you please tell me whats wrong? I am in my very early days in labview and this is infact the first program I have written. BTW i am using a serial port to communicate with the SR830 lockin amplifier. Can you tell me in this context how I use SRQ? thanks in advance.