Mitsubishi Comms

I'm working on a system with 3 identical machines, each with its own A1 plc, the 3 machines communicate data over a MELSEC network to a 4th A1 plc which then communicates to a pc via RS232, the pc runs a 3rd party data logging and reporting package for which we have no means of accessing the program or its configuration.

For the MELSEC network each of the 4 plcs is fitted with a A1SJ71AT21B comms card.

We are considering upgrading the machines' control systems one by one; the first machine needs doing straight away because the plc for that machine has gone south. Budget constraints mean that it could be some time (months/years?) before the other 2 machines are upgraded.

The upgraded control system for each machine will probably use an FX plc and a Red Lion G306.

The question is:
Is there a comms card available for the FX or can one of the comms ports on the G306 be used to connect to the MELSEC network (emulating the plc's A1SJ71AT21B comms card) so that no changes are required to either the data collection plc or the datalogging/reporting package?

We would consider using a Q series plc instead of an FX if that were the only solution.

If it is possible we would also need some programming info for the original A1SJ71AT21B comms card so that we can work out which registers are being communicated. We have no original programming documentation (comments, etc.) but fortunately the programs are not password protected so we can access and change the ladder if necessary.


edit: by the way, I have trawled the Mitsubishi website and online documentation for hours and found nothing to help me. The only documentation they have is for replacing the old MELSEC/B network in its entirity, nothing about hooking up new to old.

I apologize for the delay. I know that the G3 will not be able to communicate on that network, but I did email one of our distributors who handles Mitsubishi to see if there is a card for the FX to get on to that network and if the G3 could talk to the FX on another port.

Regards,
Dan

I just received this form our distributor:

"The FX cannot go on Melsec network but you can talk through the front port to the A series."

While I know very little about Mitsubishi, I believe that they have some option cards that plug into the PLC. I believe 504Bloke has used a 485 option card with a FX PLC to commnuicate to a G3. That way the FX could use its native port to talk to one the A series on the network and the G3 on the expansion card.

Regards,
Dan

The FX can have a BD board fitted there are 2 versions 232 & 422 or 485 they fit next to the programming port under the cover.
The best option would be the Q range as there is some documentation on changing A to Q including comms.

Thanks for your comments guys.

I kinda worked out for myself that it would be hard/impossible to get into the existing MELSEC network with an FX or G306.

I've bitten the bullet and told the customer that we will go straight from the G306 to the datalogging/reporting pc via ethernet and do the reporting in excel for each machine as it gets upgraded - ditching the existing reporting package once all 3 machines have been upgraded.

The G306 will be connected to the FX via either a 232-BD or 485-BD card (I don't think it matters which - the distance between the the plc & hmi is about 3 feet - is there any reason to choose one over the other for this distance on a point-to-point connection?)

Data logging and transfering files looks to be relatively straight forward with the G306 and the Websync or Synchronisation Manager.

The only thing I have to do now is learn how to automate the process of importing the datalog files into excel, find averages, min & max values and 95 percentile values and print out a monthly report - simple eh?? It's something we'd like to be able to do as there could be plenty more similar applications in the future.

No doubt I will be asking more detailed questions in the future as I go along but if anyone has any advice/pointers/examples in the mean time I'd be really grateful to see them.