M340 Read_Var Help.

Hello PLCTALK community, first post so take it easy on me. Also my first data move/retrieve project on Schneider platform. I am attempting to communicate between two M340's over TCP/IP. The data I am trying to move is five, 4-20 analog inputs. From the research I have done, I understand I must use read_var instructions due to the fact I have no NOC modules.
I need help setting up the read var, I have attempted numerous times but have failed. I believe my best best is to move the analog data values into %MW address, and then source these values on my master PLC using a read_var command. Any help would be appreciated. Thanks in advance!

Hi tcskier,


You can search this forum using google by entering the query as 'sitelctalk.net read_var' and you will get lots of hits as it has been discussed a lot since it is a pain in the arse since they want you to buy the NOE0100 module that does IO scanning even though it costs as much as the CPU.


Here is one thread that has some examples

http://www.plctalk.net/qanda/showthread.php?t=81026



Your application will be simpler since you will only need one read.


You are correct the modbus slave (the server with the data to be read) will have to copy the values to be read in to %MW addresses, and the client with the read_Var block will read those addresses.