What is GPIB? If I have a BNC board or RS-232C, do I still need a GPIB?

[shanna]

I want to use LabView to control an ESP100 Motion Controller/Driver. I've downloaded VI's that perform all the commands through a GPIB. I don't know what a GPIB is. I have a BNC board and RS-232C port; can I use these instead of a GPIB?

[AaronK]

Hi Shanna,
I am not familiar with your motion controller, but if it has a serial port on it you can control it over RS-232. In a nutshell GPIB is an interface that was designed to support instrument control. Many instruments have both serial and GPIB ports so you may be able to control your device with serial. The main disadvantage of serial is that it is slower and will not allow multiple instruments to be addressed on the same bus.

If it does have serial support you should be able to replace the GPIB write functions with serial write functions. In the end the driver is nothing more than a big program that takes input, concatenates strings, and writes them out over a bus.

Hope this helps out. Let me know if there is anything else I can do for you!


Best Regards,
Aaron K.
Application Engineer
National Instruments

[shanna]

Thanks Aaron!
The instrument does have an RS-232C port, so I connected this to my computer's RS-232C port (this is the COM1 device in LabView, correct?)

Now I am not sure how to change the VI's designed for a GPIB. For example, what would I replace the GPIB Send Control with? I found a VISA GPIB Command (with a Send arrow on the picture). Should I use this or the VISA Write control. Similarly, should I use the VISA Read control instead of the GPIB Receive Control?

Thanks again!

[AaronK]

Hi Shanna,

Sounds like you have the right idea. If the driver was implemented using VISA, you should be able to just switch the resource ID to use the serial port instead of a GPIB board. I am not sure which way this driver is implemented. It sounds like it was made with just GPIB commands. To remedy this I would suggest using VISA commands as you have already suggested.

Hope this helps out!

Best Regards,
Aaron K.
Application Engineer
National Instruments