allscott
Member
- Join Date
- Jul 2004
- Posts
- 1,332
I am looking at replacing an old Eurotherm EM2 temperature control system. The EM2 controls 38 temperature loops a pressure control loop and a water level loop.
The system works fine but the controls are from about 1991 and parts and technical support are starting to become an issue. As I see it I have 3 options.
1. Upgrade to an EM3.
2. Install a bank of individual controllers (we still use Eurotherm extensively) and send SP and read PV from the main PLC 5 via devicenet to them.
3. Install a new PLC to do the control and interface it with the existing PLC.
I would prefer to install individual controllers for 2 main reasons. First a single controller failure probably wouldn't cause the line to be shut down. When this line goes down for any reason it takes about 2 days to start it up again and the startup costs are huge. Secondly, I think that the individual controllers are better suited for temperature control as that is what they are designed to do.
I am being pushed to go the PLC route. People higher up than me would prefer a PLC solution quite frankly because that is all they are used too.
This is not my area of expertise so I will be doing a lot of research in the next few weeks. I am much more comfortable tuning a temperature controller than trying to tune PID's in a PLC, especially this many.
Right now I'm just curious to hear other peoples thoughts on the matter.
The system works fine but the controls are from about 1991 and parts and technical support are starting to become an issue. As I see it I have 3 options.
1. Upgrade to an EM3.
2. Install a bank of individual controllers (we still use Eurotherm extensively) and send SP and read PV from the main PLC 5 via devicenet to them.
3. Install a new PLC to do the control and interface it with the existing PLC.
I would prefer to install individual controllers for 2 main reasons. First a single controller failure probably wouldn't cause the line to be shut down. When this line goes down for any reason it takes about 2 days to start it up again and the startup costs are huge. Secondly, I think that the individual controllers are better suited for temperature control as that is what they are designed to do.
I am being pushed to go the PLC route. People higher up than me would prefer a PLC solution quite frankly because that is all they are used too.
This is not my area of expertise so I will be doing a lot of research in the next few weeks. I am much more comfortable tuning a temperature controller than trying to tune PID's in a PLC, especially this many.
Right now I'm just curious to hear other peoples thoughts on the matter.