burnerman
Member
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.
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.
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