PLC Upgrading


Thread Starter

James Martin

I am upgrading a siemens s-5 PLC and various controllers. The PLC has about 100 I/O's and the controllers handle 16 PID loops. I want to replace with a single PLC and I also want to install a new HMI. Any thoughts on how to approach this?
If you already has one Siemens S-5 PLC, it's sufficient to handle 100 I/O points. Question is, are you going to upgrade the Siemens PLC or looking for a more user friendly PLC ? If you are familiar with Siemens PLC, it should be able to migrate "other controller" into one. What's "other controller" is motion controller, or just regular PLC ?
I would suggest using a fieldbus network like Interbus, DeviceNet, or profiBus. This will allow the functional yet expandable operation of your system. This will also allow easy implementation of HMI's and 3rd party devices and not to mention easy connections to LAN's and the WEB. My personal preferance is Interbus and Dnet. These types of systems can be PLC based or even PC based. fwd questions to [email protected]

Rick Jafrate

1. Does the PLC and the controllers communicate? How?

2. What is the current HMI system? How does it communicate?

3. Connect inputs to the new system in parallel with the old system.
Use a switch or a cable arrangement to disconnect the old system's
outputs and to connect the new systems outputs. This will allow
the current system to be used for production until the new system
is installed, tested, deemed reliable, and ready for use by

4. Your choice in new equipment will be dictated by your budget and
computational requirements. What are they?

Hope this is helpful. Regards.

Rick Jafrate