PLC/HMI combo to use
PLC/HMI combo to use
(OP)
Hi everyone,
I was given the task of automating an oil heated press operation. The hot press needs two PID loops one to control the temperature and one to control the pressure. I have programmed the SLC 5/03 PLC before but only to control discrete outputs to open/close valves, alarms etc. Never dealt with analog signals. I need some guidance on which would be the combo PLC/HMI combo to use that will be the easiest to program and configure. Are there any PID modules on any PLC manufacturer that I can use to control the temperature and pressure? Can they be interphased to an HMI so that I can start the loops from an HMI screen? Does it have to be a PLC?
Any help will be appreciated.
Thanks,
I was given the task of automating an oil heated press operation. The hot press needs two PID loops one to control the temperature and one to control the pressure. I have programmed the SLC 5/03 PLC before but only to control discrete outputs to open/close valves, alarms etc. Never dealt with analog signals. I need some guidance on which would be the combo PLC/HMI combo to use that will be the easiest to program and configure. Are there any PID modules on any PLC manufacturer that I can use to control the temperature and pressure? Can they be interphased to an HMI so that I can start the loops from an HMI screen? Does it have to be a PLC?
Any help will be appreciated.
Thanks,





RE: PLC/HMI combo to use
Regards
Roy
RE: PLC/HMI combo to use
Are these two loops (temp and pressure) interrelated? Maybe you should be looking at cascaded or other multi loop control strategies.
RE: PLC/HMI combo to use
These 2 loops are part of a recipe. The temperature loop and pressure loops should be started simultaneously. This should be done on a single "cycle start" switch. I'm trying to prevent the operator from forgetting to start either one of the loops. This is why I'm trying to use an HMI where I can create a recipe and download it to the controller. With a soft internal switch start both loops at the same time. I know it can be done with a PLC but it requires a lot of programming.
Thanks for your suggestions,
RE: PLC/HMI combo to use
A PLC such as the SLC 5/03 for example, has a built in software PID loop instruction, and just requires some analog I/O. It could also be used to store your recipe values, which could be accessed by a PanelView perhaps, removing the need for a PC.
PC based HMI and recipe control can get expensive, so unless it was part of a larger system, I'm not sure I would go that route.
RE: PLC/HMI combo to use
Thank you for your reply, It is a stand alone system. This press is for use on our R&D department. This is why we don't want to spend too much money on this project. How difficult is it to program PanelView to be able to access this PID loop instructions?
RE: PLC/HMI combo to use
In this example, the PanelView would then access N10:2 to read the Setpoint value.
The SLC instruction set manual maps out all the registers for you.
RE: PLC/HMI combo to use