rs485

[Joseph_Loo]

Just to make sure I am working on the same assumption, I have the following questions.

1. Are you using one of the RS485 cards from NI? Does it have multiple communication ports?

2. You have configured the RS485 card using max to make it a 2 wire duplex configuration

3. Can you get a cable and loop the RS485 ports together.

4. You are using the correct communication ports?

The symptons you describe sounds very much like the problem I have when my ports default to the 4 wire setup.

[aznw82]

yes, i'm using the rs485 card and i did change the wire configure to 2wire auto. if that doesn't work, i also used the rs232 to 485 converter on the comport.

the comport is in the right setting, i'm getting response back from the loop back test. so, i don't think its related to the connection.

[Joseph_Loo]

This is how I communicate with my rs485. I have an initialization file, a vi to initialize the rs485, and one to read and write the data.

[aznw82]

do you have the whole labview program, i'm still learning about labview. so, i'm not sure about most of the icons in your pictures.

thanks..

[Joseph_Loo]

This is a aip file. I use Labview 8.2.1.

[Joseph_Loo]

Forgot the attachment

[aznw82]

thanks.

[aznw82]

after looking those serial lib. i don't quite get it how it works. have a question, how i send a bunch of 16bit messages to RS485?

[Joseph_Loo]

My setup has the serial controller running as a separate thread. I send a command via a queue to the serial_controller vi. When it is sent, it sends the response back via a queue (Serial_Out, Serial_In). The queue name is determined in the configuration file sent to you earlier.

I thought you would modify it to suit your needs. I have multiple threads accessing the same serial port. In addition, you will need to find the correct device name/communication port. The configuration file also contains the communication port via Resource(ASRL1::INSTR).

[Joseph_Loo]

I re looked at my code. You want to look at CMd_Read_Write in the serial controller. This is the easy interface to the device. You will need to make sure that the proper communication port is selected and the repsone value set to 0.