RS232 communication works, RS485 doesn't..?

[Daniel.S]

Hi,
I'm programming serial communications on a T7A. So far I've been using RS232 and I have working code for both sending and receiving data (output via COM1, input via COM3). To eliminate external errors, I'm looping from COM1 straight back into COM3 - I basically use no other devices whatsoever and it's working fine.

However, I need to switch to RS485 instead ( COM2 and COM4 set for RS485) for the actual communication. The only code I changed was setting input and output to COM2 and COM4 respectively.

No data gets sent, confirmed via maxterm and a RS232/485 converter. What am I doing wrong?
Thanks for your help!

[Jae V]

Hello,
We understand that this is a very old post. The reason the 485 COM doesn't work is because it has a different Pin out then the 232. So even though you changed the setting in the panel, the cable would need to be changed. The pin outs can be found in the controller help manuals. If there is anyone who is still experiencing this or similar issues and require assistance, please visit us at https://www.beijerelectronics.us/en-US/ ... ___support or give us call at 801.708.6690. Thank you.