SattCon 15 and RS485 to multiple iFIX PCs


Thread Starter

Mark Taylor

An existing application consists of two SattCon 15 PLCs connected with 4-wire RS-485 from CH1 of the SICB COMLI interface. These are connected to a Radio Spares RS232/485 protocol convertor. The DTR+/DSR+ and DTR-/DSR- terminals are tied on the 485 side. 2-wire RS-232 is then run from the convertor to the PC. The DTR/DSR terminals are tied on the 232 side. Not sure at this stage of any looping at the PC end. The iFIX driver 'SCC' is basically an RS-232 driver (COM port).

I want to connect to two iFIX PCs since these are setup in a master/standby arrangement. I imagine I will have to convert to 2-wire 485 since there will be multiple masters.

Does anyone know if the SattCon 15 will support 2-wire 485? Would it be preferrable to put RS-485 cards in the PCs or go for an extra protocol convertor? What else do I have to look out for?

Richard Hind

The SattCon15 can use 2-wire comms if required. It is selectable via links on the SICB. In my experience I have always used Westermo modems with 100% success in instances like this. If you wish to use your existing comms hardware I would recommend using Westermo MA42 modems. These are 485 to 232 converters. Use one at each node i.e Both Sc15's and both PC's. MA42's will also give the required protection and distance. SICB's should only be used for short distances.

However, by far the best solution to your problem would be to use SattBus. This is a token passing bus 2-wire bus with upto 120 nodes and can communicate upto 1200metres. It is specific to Satt. Each node on the network has its own SattBus connector with a unique identity. Therefore you would need 4-off at approx £420 each. SattBus is very easy to configure and provides a more robust comms connection. SattBus connectors come in two versions 232 or 485. I have used SattBus on many installations without any problems as long as the insatllation guidelines are adhered to. i.e correct cable type.

Hope this helps.