cDAQ-9137 RS232 RJ45 Port

[User002]

I try to use the RS232 RJ45 port on cDAQ-9137 chassis to comunicate with CSZ thermal chamber.

I use a RJ45 to DB9 converter (Digikey Part # 602-1506-ND) with a null-modem (crossover) cable (Digikey Part # TL642-ND) to connect between cDAQ and CSZ thermal chamber. 

The CSZ thermal chamber use Modbus and only pin 2, 3, and 5 is present. I made the labview program to talk to the device and tested using my laptop with USB-COM converter. and the program works with no error. 

Once I switch to cDAQ and use the same program. The error in MODBUS read presents. I shut down both cDaq and thermal chamber and restart them but it still won't work. 

I used COM1 in cDAQ for this communication testing. The cDAQ also used a Virtual COM3 (VCP) to communicate with other device. 

Seems like the port on cDAQ has some problem or I didn't configured it properly. 

Any recommendation and advice is appreciated. Let me know if further information is required. 

[Danubio]

Hi Luyi,

Have you made sure to have installed NI VISA in your cDAQ?

Regards,

Daniel C.

[User002]

Hi Daniel,

Thank you for the reply. in NI MAX, the COM1 is visible.

Eric

[Danubio]

Hi Eric,

Try making a loopback test on the cDAQ's serial port to make sure it is configured properly.

http://www.ni.com/tutorial/3450/en/

Regards,

Daniel C.

[User002]

Thank you for reply.

I compared the pinout from cDaq manual with the converter cable from Digikey. They are not the same.

cDaq uses 8 and 9 for TxD and RxD. However, EIA-232D dictates 5 and 6 for TxD and RxD. 

I'm ordering converter cable from NI (#182845-01) to fix this. This is not the first time that a simple regular hardware off the shelf somewhere won't work on NI.

I will get the cable in a week and will try it out. Thank you all for the help.