We have a Ti545-1104 processor which we want to communicate with Citect via PLCs programming port and the PCs serial port with a distance of 70 metres. I have tried using RS232-RS422-RS232 converters but always get a <communication time out> error. Any specific solutions would be appreciated.

 

You could probably go 200 feet with good cable and a reasonably slow baud rate. But why not just use 232-fiber transceivers at either end? Cheap, with noise immunity and electrical isolation thrown in for good measure.

 

Well, the 545-1104 has two ports for comms: one is RS232-only; the other is RS232 or RS422 or RS485 depending on the cable connections you use and a single dipswitch setting. Why bother with converters? Go RS422 or RS485 direct and you should cover this distance easily. If you only have RS232 at the PC end, at least you can eliminate 1 converter.

The 'comms time-out' issue sounds like a completely separate problem to me. Electricity doesn't take that long to flow down a longer wire!! My guess is that your existing PLC connection + converter connnection + converter connection + Citect connection has a misconnection somewhere. I don't know what this message indicates in Citect, but in Tisoft a 'comms time-out' simply meant that the software thought it had sent a message but had not received a reply. 9 times out of 10 this would be a cabling error or incorrect port assignment.

Regards

Ken