RS485 serial communication

[Humaid93]

I using the attached example to communicate with a temperature unit from Eurotherm. when I run the example it gives me the error (attached picture). The error accured with and without choosing the visa resource name. I installed the required driver. could anyone give me hints what is the reason for the error? 

[Humaid93]

I am working with a device called owlstone which has two units (V-OVG and OHG). Those units are connected via Rs485 2 wires TX and Rx with ground. In order to communicate with the devices, using the same protocol and echo converter from rs485 to rs232  to be connected to a computer.

Now how do I check if the setup communication is working? I tried to use the attached example to communicate with subunit (Eurotherm 3216) at one of the devices V-OVG. Visa resource and address unit are known. The example crash when I run it and it gives me an error as shown in the attachment. Could someone tell me what is the possible reason for the error? and how to test if the communication is working? Any hints would help.

keep in mind that I tried different connections Tx and Rx in Rs485. Also, the shield of the cable is connected at both ends with devices and with the computer. 

[cbutcher]

As a quick first check, you say that the VISA resource and address are know. Are you setting these both before you run the VI?

The values will be read when you click Run, and changing them later will make no difference.

Further information about the error you're receiving can be found here: Error -1073807346: The Given Session or Object Reference Is Invalid in NI VISA.

[Humaid93 · Accepted solution]

solved, the problem was on hardware.