HELP!!, I got to program a Fanuc PLC

Hello everyone,

I've been doing electrical maintenance for about 10 years now. I recently took a new job and the boss informed me that he wants to write a program for a machine we are building. I know how ladder logic works and can read it, but I've never written a program before. Are there any study aids or anything that any of you can think of to help me out. I feel a little in over my head and i'm not sure where to start when it comes to writing an entirely new program for a new machine. Any help you can provide will be greatly appreciated. This is for a Fanuc controller.

I prefer Fanuc to other PLC's as I think they are they most straght forward to program. When you get a chance, post the PLC that you are using and the software. I myself am most familiar with the 9030 series, the Micro 90's, and the old Series 1 (same as Koyo/Automation Direct 305 series and others). I generally use Logicmaster to program (I like DOS), as opposed to versapro and cimplicity.

Are you just writing the program, or do you need to configure the PLC and rack slot assignments also?

Here's how I start:

1). List all inputs, making a seperate list for AC, DC, and analog inputs. Generally, I'll only have one type, sometimes two, and on a rare occasion, all three.

2). List all outputs, AC, DC, and analog. Generally, I only use Relay output cards, but try to keep AC and DC on seperate cards. Only on a rare occasion do I have an analog output, if I do, it is most likely hooked up to a meter.

3). Determine the total number of input and output cards.

4). Assign the inputs and outputs to the corresponding devices. This would also include the "TAG" identifier, such as input 5 / limit switch 2 may be I05 / LS2. I assign wire numbers at this time. Input 25 would be 325, output 12 would be 412, etc.

5). Determine the sequence of events for each output. I usually sketch a simple 1-line schematic for each output, then assign my inputs from there. This would show "and" "nand" "or" and "nor" logic, timers, etc.

6). Then work on anything fancy, timers, one-shots, latching relays, resets, registers, or my favorite (?) drum sequencers.

7). if it is a complicared rung, I'll start off with an "Always On" contact, in case I want to disable the rung during Debug, it is easy to toggle, and to me it is easier to put it in up front, than on the shop floor. It can always be easily remove (or left in). Also, pretty quick and easy to reassign for whatever reason, such as an internal MCR.

Anyway, that's a start. Post more info if you can. No doubt, others will jump in. Everyone has their own way to do it.

regards......casey

Tell your boss I am available, reasonably priced and have the software and adapters for GE Fanuc's PLC.

You can PM or email me and I will assist you in this...regardless.

It is a 90-30 series and we have Cimplicity software. And, to answer your question, yes I will have to configure the slot assignments for the cards.
Thanks for in the info to get me started, I will certainly use it.

I have allot of manuals in PDF form if needed..

Gary

An acquaintance of mine, who once worked as a field service technician for an OEM we both worked for, later took a job with one of our customers. He told me how he used to ridicule us in the Controls Engineering department for the lousy programs we wrote... until the day when he had to write one himself. He said it's easy to see a way to do something better when you're looking at someone else's efforts, but it's an entirely different matter to come up with something from scratch.

The tyranny of that blank sheet of paper can best be overcome by breaking down the overall control scheme into more manageable pieces. Pick some part of the system that you know well, and try to write the program to control that. Test it, revise it, and test it again. Once you're satisfied with your results, move on to another small piece and repeat the process. If, in the course of programming some portion of the system, you discover a better method that applies to something you've already programmed, don't be afraid to go back and redo your earlier efforts.