Modbus communication

We have a Power analyzer that we want to monitor with our OPTO 22 control system. Both the Analyzer and the OPTO 22 are slave only devices.

Is there something we can use in between the two as a master and be able to send the data to the OPTO 22?

This is new territory for me so any help would be apprecated.

There are quite a few things that you could use.

What kind of interface does the analyzer and Opto 22 controller have? RS-232, RS485, RS-422?

If they have a RS-485 or RS-422 connection, you could use a DL-06 from AD as the master to both of them and have it act as the "bridge". There are probably quite a few PLCs that could perform this just as well, this is just one that I am familiar with that is priced pretty reasonably.

If they only have a RS-232 connection, you could technically use a RS-232 to RS-422/485 converter on them as well but that sometimes gets trickier depending upon the devices. I believe that AD makes a converter that could probably do the trick as well (FA-ISOCON?).

There are probably some dedicated bridge components out there that could do the trick. I personally like using a PLC because it gives me some flexibility in the mapping and possible data type conversions if necessary.

It sounds like Opto does has something for you. The blurb from the Opto web site (below) indicates that Opto has some path that implements a Modbus RTU master.

http://www.opto22.com/products/ProductFamilies/modbus_sys.aspx

The Modbus OptoIntegration Kit allows Opto 22 controllers using OptoControl to communicate via a serial port as a master or slave using either the Modbus ASCII or RTU protocol. The kit is a set of OptoControl subroutines that transmit and receive message strings according to the Modbus specifications. These subroutines transmit and receive Modbus messages using Opto 22 controller serial ports and Modbus standard coil, input, and register numbers. The data is then stored or retrieved using OptoControl numerical tables.

Dan

Power Analyzer ModBus

And, the power analyzer will 'act' as an ModBus Slave unit. So, with OPC configured properly and proper drivers, you should have no problem communicating.