CP341 and CP441 Serial & Modbus Communication

Goodday All,

I have searched the forums and read the manuals for these devices and still am unsure on some items.

I am currently doing a S5 to S7 upgrade and need some expert assistance on the serial communication. On the existing S5 there is redundant 135UPLC's with 2 CP524 interface modules communicaating to Honeywell DCS via the Modbus Slave Serial Driver. There is one expansion rack with 3 CP524 Modules.

Communication Specification according to the existing drawings:

2 * CP524 on Main PLC Rack (To Honeywell DCS)

Protocol : MODBUS

Communication Rate: 19200bps

Parity: even

Characteristic: RTU (8bit memory)

Modbus Device No: 2

Comm Mode: RS485

Stop Bit: 1

CP524 (1) on Expansion Rack (To iFix Scada) - This has been removed to acc for Siemens HMI talking on Ind Eth

CP524 (2) onExpansion Rack (To 2 * C.C.C Series 3 Plus Controllers)

Protocol : Siemens 3964R

Communication Rate: 19200bps

Parity: even

Characteristic: 8

Comm Mode: RS422

Stop Bit: 1

CP524 (2) onExpansion Rack (To 1 Governer)

Protocol : Siemens 3964R

Communication Rate: 19200bps

Parity: even

Characteristic: 8

Modbus Device No: 1

Comm Mode: RS485

Stop Bit: 1

My new configuration consists of 2 * CPU414-4H PLC's with 2 * CP441-2 Interface Modules to replace the CP524 with 2 Modbus Slave Dongles and Software and a CP443-1 to communicate to the HMI (this has replaced one of the Cp524 on the existing expansion rack). I have a redundant ET200M IM153-2 to replace the expansion rack with 2* CP341 to replace the CP524. I have one master modbus dongle for the CP341 communication to the governer (1 device).

My questions are:

1) Is it possible to communicate to more than one device using the Siemens 3964R protocol with RS422. If so how do you configure the blocks FB7 (P_RCV_RK) and FB8 (P_RCV_RK) to know which device to communicate with. From my studying on the forums and product documentation I am leaning towards this being a Modbus Master aswell even though the existing drawings suggest otherwise.
2) How do you set up the Modbusslave configuration in Netpro to communicate to the Modbus Master (CP341). I have tried to add a other device in step 7 with PTP interface but I can only add 2 devices on the PTP network. I understand that it is point to point but there is no Modbus interface to choose from.

Some help in this regard will be greatly appreciated.

Regards,

Grant