I have two electrical meters that are communicating to two external users (via DNP3). Each user requires data from both meters. I have two serial ports on each meter.

One of the serial ports on each meter is used for the external communications. I can connect the two meters together on the second port. I can make this work one-way by setting one meter as the master and the second as a slave. How can I get data from the first meter to the second at the same time.

 

Modbus master is able to read data (e.g. obtain from Dev1 into Dev2) and write data (send data from Dev2 into Dev1). Since this is bi-directional, one serial connection should be sufficient to provide the bi-directional comms.

An alternative would be that you install a Modbus Master OPC Server on the computer and an OPC bridge software component (e.g. DataWorX32). You can download it from
http://www.iconics.com/support/free_demos.asp
Now the bridge software will communicate the changes in values between the two (or more) devices.

regards
Raymond van der Tas

 

I assume that the Modbus Master meter is reading from the Modbus Slave Meter. Is it possible to make the Master write its data to the Slave meter?

John Rinaldi
http://www.rtaautomation.com/modbustcp/