SAIA PCD2 Modbus

I need to interface a SAIA PCD2.M120 with a modbus link to foreign system.
Anyone done this with the good old DOS editor, i.e. anyone have an example program for this?

Yes. I wrote some PG3 code with the PLC as Modbus (RTU) master supporting the functions 01 (read coil), 03 (read holding register), 15 (force multiple coils) and 16 (Preset multiple register.
Besides using Modbus, there are some questions
- is the SAIA PLC going to the master or slave?
- is it Modbus ASCII or RTU ?
- which functions to use?

Hei.

See attachment for description of protocol, which according the manufacturer is more or less standard Modbus.

SAIA will be master.

We shall fetch some analogue values and common alarm.

I don't expect You to spend time and effort to help out here, but if possible explain a little bit of the modbus project You mentioned. Which card type/port did You use, what kind of initialising text etc. If possible I would appreciate If you could send a copy of the source files which regards the modbus interface.

Hei

The attached pdf-file doesn't provide much info about the JBUS/Modbus interface. Only that the interface is RS485 and that communication data is organized in a gateway buffer of 114 registers.

There are missing information about baudrate, slave adresses, supported JBUS/Modbus functions (since the data is organized in registers, read and write registers should be supported) etc.
There should be information like this: http://www.eurotherm.com.au/other/pdf/memocal_modbus.pdf

Regarding HW. With SAIA.M120 a RS485 interface can be equiped on channel 1 or 3. E.g. PCD7.F110 on ch 1. Assign the channel to Mode MC4, RS485 ASCII. A PLC program must be written to send and reveive data according to chosen functions in the JBUS/Modbus protocol.
I'm sure you understand that I can't give away the source files.