Communication (RS-485) of a micromaster 420 with labview

[espartan117]

Good be late forum, it wanted to request his help them with the following thing, nowadays I am trying to communicate a speed variador Micromaster 420 with Labview by means of a protocol of communication RS-485, to do the communication of a physical way between the computer and the variador am using a convertor of protocol of Rs-485 to USB, As for the application that I did in Labview, it is formed so that it could communicate by means of a serial MODBUS, but the problem is that when I try to traverse the above mentioned application, Labview says to me that it has not connected at all in the port USB, there is some special way to form the serial Modbus so that it recognizes my convertor or they can recommend to me some another way of solving this problem?

[smithd]

Hello Espartan,

First, I wanted to be clear and confirm my understanding of the issue:
1) You are attempting to communicate to a Micromaster 420 over Modbus Serial RS-485

2) Your PC does not include a RS-485 port, so you are using a USB to 485 converter

3) You are recieving some sort of error stating that the port was undiscovered

Assuming all of the above is correct, you can try the following:
1) Make sure that the visa port is selectable. If you go to your windows device manager you should be able to see the USB device and the COM port it has been attached to. 

2) If so, then you should go to NI MAX/devices and interfaces, right click on that port and access visa test panels. These test panels give you an interface through which you can perform a loopback test.

3) Assuming you can perform a loopback test from NI MAX, you should either call into your local NI support group or post back here, as the troubleshooting will be more in-depth.