Modbus 485 issue

[SUTHAN]

I am new to unitronics Visi logic software. i am using V1210 controller at site. i need to do an modbus 485 communication between an GE controller an V1210 controller here GE controller is an master and unitronics V1210 as an slave i need to sent all my MI and MB used values to GE controller. In this case i need to write my data to GE PLC i searched in unironics there is read block is present but write blocks are not there.

how can i write my data to GE plc please guide me on this if you have any reference logic for the same please share with me. i already created logic for configure the modbus 485 communication and Port initialization logic.

thanks in advance. 

[Ausman]

You have a master/slave issue here.  And the magic word for looking at what you want is FBs/Modbus/Preset.

You'll either have to have the GE poll (often) the V1210 slave periodically to get the updated MI & MB values, or implement a change in the slave/master relationship so that the 1210 can send them, using "Preset", as the Master, to the GE.  The GE may have a function where it can act as Slave/Master, which would make this easy.  Examples exist showing how to change the 1210 from master to slave, but labelled as "V130_Modbus_Master_Slave_switch".

Other forum members might have a workaround, but to me this is the essence of the issue.

cheers,

Aus

[Flex727]

Ausman is correct (as usual). Only the Master can Read & Write. The Slave merely listens for requests from the Master and allows the registers to be Preset (written) or Read. The Slave cannot initiate action (at least directly).

[SUTHAN]

Thank You   Mr. Flex & Mr. Ausman