08-23-2018 11:49 AM
Hello,
I am trying to read back the temperature from the Thermotron 3800. I have attached my code. After sending the read command "PVAR1?", I get gibberish from the bus:
Can you offer any advice as to why this may be happening?
FYI...I am able to START and STOP the Thermotron chamber by sending the relevant commands.
Thanks,
hiNi
08-23-2018 12:35 PM - edited 08-23-2018 12:53 PM
Hi hiNi,
Make sure all the serial settings (baudrate, termination character, flow control) for your labview code match Thermotron 3800 documentation. If you are using the visa configure port vi, labview by default enables the termination character to line feed character '\n' so something to consider.
How many bytes are you expected to read back? you want to make sure you give the serial port enough time after you write to return all the information. play around with your time delay.
I would also suggest you start by looking for the Basic Serial Read and Write vi in the labview examples library and play around with that first. In your menu bar, under help, find examples, type serial and you'll find it there. Set the baud rate and everything and then send it PVAR1? and see what happens. Good luck!
- Serge
08-23-2018 01:35 PM
Hello,
I used the attached downloaded example for the 3800 but I still get the error. I used the "thermotron chamber controller gpib example using visa.vi" but still get the error. The chamber starts and stops without any issues, but I get gibberish on the read. The program does ask for the following:
Instructions: 1. Ensure the resource specified in the VISA GPIB Resource control is properly configured in NI Measurement & Automation Explorer. (Devices and Interfaces, GPIB0, Properties = Use defaults except for Termination Settings: Send EOI at End of Write, Terminate Read on EOS, EOS Byte = 13, 8-bit EOS compare, Set EOI with EOS on Write) 2. Chamber controller I/O GPIB setup: Send EOI = yes, Terminator = CR, Send Ack = yes 3. Run the VI.
How do I go about making these setting in NI MAX 18.0?
Thanks.
08-23-2018 03:26 PM
Are you not able to see your device connected in MAX under devices and interface?
This might help you:
http://www.ni.com/tutorial/2761/en/
- S
08-24-2018 09:51 AM
Hello,
The computer is able to recognize the equipment:
I am using NI Max 18, I do not see the menu to change the GPIB setings as mentioned in the example from Thermotron:
I am thinking that this may be the source of me getting back gibberish from the gpib bus??
How do I go about making these changes in NI Max 18?
Thanks!
08-27-2018 05:29 PM
I am thinking that this may be the source of me getting back gibberish from the gpib bus??
Yes, most likely.
How do I go about making these changes in NI Max 18?
I don't have the latest version of NI Max or any gpib devices to test with so i'm not sure why you can't access these settings. They should be there somewhere. Sorry i can't be more of help.
- S
08-30-2018 01:45 AM
I don't think you've terminated your string command.
Try PVAR1?\r\n