We are interfacing 3 A-B PLC's with MODBUS TCP that are mostly reads, but some writes, to a R410 Honeywell Experion system. Some of the PLC data will be used for logic in the C300. In total, we're only talking about 400-500 coils and registers. Should these all be in PCDI, or a mix of PCDI and SCADA points. Since a lot of these are read only values, it might make sense to do a mix instead of loading up the C300 if only PCDI is used. I'd be interested in anyone's experience on doing this, especially if there were any C300 loading issues because of PCDI. Seems to me that using a PCDI/ SCADA mix is going to create more MODBUS calls, which will cause more overall loading on the system.

 

Please can you explain PCDI?

Also - Have you checked the Experion "Sinewave" and "Page 10". Since you are talking on 500 points I do think you will be OK.