alexo35
Member
Just for a little backround.... I have been in the electrical field for 6yrs and have been involved with PLCs for the past year or so. I am now the only electrician in our plant and am solely responisble for our automation system.
My question comes from the fact that this is the only PLC system I have ever seen / worked with and do not know the "standards" for doing things.
Our plant consists of 7 major machine centers and the connecting conveyers. Some machines have thier own dedicated PLC for the machine and conveyers. Others have thier own PLC, but rely on another for the conveyer system. Still other systems still have hardwired start / stop operation.
The PLCs are on a serial over Ethernet network. This is a monitoring system only with no control elements. All PLCs are Idec, most FA3S, some FC5A.
This approach makes it difficult to modify the system when changes are made.
I have thought about adding more controllers so that each one runns its dedicated system and no more. Each machine would have its own PLC. The conveyer systems would be seperate, and the consoles would have thier own to with a serial connection to the "main" PLC for the machine.
Real question:
1. Would this be considerd poor practice?
2. Is there a general rule on thumb for how complex a system needs to be to justify its own PLC?
3. Can I run the outputs from one PLC to the in of another for communication. I know it works, but is this "bad practice".
4. Any other advice?
Thanks for any help. Our PLC system was quite the mess when I got here. No I/O labels, no rung labels, no descriptive anything. So I have come a long way on my own, but it's time to ask for help.
--Alex
My question comes from the fact that this is the only PLC system I have ever seen / worked with and do not know the "standards" for doing things.
Our plant consists of 7 major machine centers and the connecting conveyers. Some machines have thier own dedicated PLC for the machine and conveyers. Others have thier own PLC, but rely on another for the conveyer system. Still other systems still have hardwired start / stop operation.
The PLCs are on a serial over Ethernet network. This is a monitoring system only with no control elements. All PLCs are Idec, most FA3S, some FC5A.
This approach makes it difficult to modify the system when changes are made.
I have thought about adding more controllers so that each one runns its dedicated system and no more. Each machine would have its own PLC. The conveyer systems would be seperate, and the consoles would have thier own to with a serial connection to the "main" PLC for the machine.
Real question:
1. Would this be considerd poor practice?
2. Is there a general rule on thumb for how complex a system needs to be to justify its own PLC?
3. Can I run the outputs from one PLC to the in of another for communication. I know it works, but is this "bad practice".
4. Any other advice?
Thanks for any help. Our PLC system was quite the mess when I got here. No I/O labels, no rung labels, no descriptive anything. So I have come a long way on my own, but it's time to ask for help.
--Alex