Hi,

I'm new using Modbus and would like some help, if possible. I have an application where I need to output data in Modbus format over Ethernet to Experion Software. I believe Automation Direct's H2-ECOM 100 module is all I need, but not sure.

Once the PLC process is done, I need to download all my user inputs (Recipe data) to Experion. It appears all I need is to use a conversion sheet that targets V memory. Specifically, I just enter the V memory into the spreadsheet and it tells me the Modbus number to use.

I have not worked with Experion, but am assuming this Modbus “number” is what the Master needs to pull that data. From a PLC ladder logic point of view I don’t have to write any additional logic beside the Load and Output for assigning user inputs to receipt V memory…Correct?

I appreciate your time. Thank you.

 

Sounds to me like you have the overall right idea...
Bill

 

Correct. With the 205 PLC, Modbus/TCP comms to an H2-ECOM100 (or Modbus RTU comms to Port 2) target the same block of V-Memory you address in ladder, so you don't have to move the data you're interested in to a special location or anything like that.

To make it even easier, the addresses (for Modbus FC's 3 and 16) are even the same, once you allow for the fact that ADC memory addresses are in octal. V2000 is Modbus 1024, for example (you might see it as 1025, depending on Experion's implementation of Modbus).

Coils are almost as easy. Convert the "C" address to decimal and add 3072, IIRC.

You don't even need to use ADC's spreadsheet if you don't want to. Excel has the DEC2OCT() function in the Analysis Toolkit, and between that and drag-and-fill, you pretty much have everything you need.