Comport symbol

[HelgeT]

Hi,

I am trying to communicate with a Modbus sensor over "2-wire Auto" RS485.

I have two NI USB-485-1 devices. Both are configured the same way in MAX and Control panel. The one on COM13 communicates without problem. The one on COM8 does not communicate at all, resulting in framing errors, unexpected I/O errors etc. from VISA. Same wiring to sensor used on both.

In the comport selection control, I see a symbol to the left of COM8.

 What does it mean? Any help appreciated.

[Dennis_Knutson]

It simply means that there is an open VISA reference to that port.

[smercurio_fc]

The Small Symbol In the VISA Resource Name Control/Constant

Ain't search wonderful?

As for your framing errors, those are almost always related to hardware issues. A framing error is generated by the UART that's handling the serial communication, and it's indicating that the serial frame was invalid (e.g., wrong baud, wrong number of stop bits, wrong number of data bits, etc.). This could be wiring problems, such as loose connections, or noise on the line.