Powerflex 525's controlled by Idec FC6A

I've been presented with five PF525's with embedded ethernet ip. They need to be controlled by an Idec FC6A plc.

I skimmed a PF525 manual when I first learned what they were planning and saw "Modbus" in it and thought it was good. However, I believe they are only capable of Modbus RTU which is more a serial based multi drop control. The Idec plc has no Ethernet IP capability. Only Modbus TCP.

I'm looking at options:
1. Idec makes a FC6A-SIF52 Comm Module for the PLC which allows it to have RS485 and the plc is capable of Modbus RTU. I've had one of these cards on order for 2 months and am looking at 4 more. So, thats out.
2. An Ethernet IP to Modbus TCP converter came to mind. I believe Prosoft and Anybus make one. I feel like they may be pricier with a possible lead time....
3. Or what about a 3rd party, Modbus RTU to Modbus TCP converter? Anybody have experience with this in a similar application? There seems to be several manufacturers and I would hope someone would have one on the shelf.
4. Other options?

TIA

Is there a good reason for using a controller as lilliputian as the Idec FC6A for this application ?

I assume you're using the FC6A "All In One" model, not the FC6A Plus, which does have EtherNet/IP Scanner and Adapter capability.

Doesn't the FC6A serial port support Modbus RTU Master directly ? You could just daisy-chain it to the RS-485 ports on each of the PowerFlex 525 drives and write your code to poll them in sequence.

Ideally you would also use an RS-485 isolator between the PLC and the drives, but you can certainly bench test it without one.

OK, I admit, I had to look up the definition of "lilliputian". Great question. I got grandfathered on the Idec plc. The FC6A seemed like a logical upgrade from an existing, obsolete FC5A, to avoid having to re-write all the logic.

My Idec support guy just replied back that the Ethernet 2 port is capable of Ethernet IP, as you did. Great catch. So, I am going to dig into that.

To get a serial port on the FC6A, you have to get the option card for it, which is a long lead time item.

Thanks so much.

Oh, so you've got one of the All-in-One models that doesn't even have Serial Port 1 built in.

If it's got Modbus/TCP Master and the ability to designate a Slave ID number, I would recommend a Modbus TCP/RTU gateway.

The least expensive is probably Automation Direct's MB-GATEWAY. Others are available from Moxa, Digi, Avantech, etc.

Just be sure you get a module that supports Modbus TCP to Modbus RTU "gateway" functionality, rather than being a general purpose Ethernet/Serial "device server".

Its the MicroSmart FC6A Plus PLC, pt. no. FC6A-D32P3CEE. Serial ports are a separate card. As luck would have it the serial port card is the only part in this setup with a long lead time.

I took a look at the setup for Ethernet IP on Ethernet Port 2. Whewww. It might be the way to go but I need to get a PF525 hooked up and try it out.

I think you're right a cheaper, and probably simpler route might be to go with a Modbus TCP/RTU gateway.

Interesting note on the EIP capability of the FC6A Plus. It can act as a scanner or adapter. It might be anoption for those with Logix processors and no I/O cards....

Just a quick update on this. I did go with using Ethernet IP on the Ethernet Port 2 on the FC6A. This was networked to the five Powerflex 525's. Its been working flawlessly for several months now.