ModbusTCP - Server - PN & CP - 314-C

Was hoping for some help trying to establish communication. I have a 314-C PN and a CP-343-1 both acting as a ModbusTCP Server (for redundancy). I have the CP343-1 working smoothly, but struggling with the PN port. I have both sample projects for CP and PN and have just copied the OB1/OB100 code across (had to tweak a little to avoid duplication). Could somebody take a look at the attached and see if there's anything obvious that's missing? I have a couple of things to try tomorrow, but beyond that i'm struggling! :(

Thanks

Rob

If the MODBUSCP call in the OB100 finishs without error the block is ended by the BEB and the MODBUSPN is not called in the OB100.