PLC, contactor and wiring migrate/upgrading advice 1

[franz03]

Hi,

I am new in project engineering and my previous work is PLC programming only. For experienced engineers, what are the step by step procedure that you use in migrating/upgrading and what are the things that I will avoid?

 

[itsmoked]

franz03: I'd recommend doing your homework! That is, page back down this forum and check all the "how PLC" threads you see. Skip any specific how to questions about specific PLC types.

This has been discussed several times to great extent in here. It will help you formulate a more specific question(s) and further your knowledge.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[eeprom]

Before you do anything, document the existing system as well as you can. You need to be able to identify every single signal, it's voltage/current and scaling. Make sure you thoroughly understand every line of the program that's in service now. There are no programs available for migration/replacement that are worth using. You will be re-writing the program, and that's a good thing. When you do this, write the program as if you are never going to return to the plant. Pretend you are moving to China, and you'll have no phone service. There should be so much comment and documentation left behind that anyone with PLC skills should be able to follow your logic. Every single line should be commented. Your comments should add up to a functional description of the entire program. Don't assume that anything is obvious.

You should have everything written and bench tested before you make any attempt at changing out the existing system. Have a written plan for field testing. Don't burn your bridges. If you start taking things apart without a plan, life will become painful quickly.

EE