I started with hard wired logic, Solicon, NorBit followed by Logicon 1 & 2.
Texas Instruments was the first PLC systems we used. We went on to Mitsubishi Medoc. Which I still like.
I moved to another company where Modicon ruled, one look at it “it’s the same as Taxas Instruments”.
If you enter in to an established company that is already using PLC’s or what ever, I’m sorry but you’re in at the deep end. Most companies will put you with an experienced guy for a while. If he’s any good he will take a back seat as soon as possible, just giving you hints when you’re going off course. The last one I was with took it to the extreme, he stayed in the mess room drinking tea while I was doing the blue arsed fly impression.
One of the most important things is to learn the process. As with any process the operator can be you’re best friend or sworn enemy. Those that will give the right information and those that want to sit on their arse while you flounder around.
To go in to industry now and PLC’s are a fact of life, how far you go with them is between you and the company. Some will have Fred in the office that does all modifications, other like the last one I worked for will give you more than enough rope to hang yourself.
Enough rope? I got in to an argument with one of the directors. One program would get it’s self in to a loop and refuse to do anything. I’d been there two months and was told to get on with a total re-write of the program. Took three months on and off to write. Got there in the end. Talk about flying by the seat of your pants.
I got so fed up of my programming being blamed for one machine going wrong I put a monitor system in the program tracking what the operator was doing. Didn’t tell anyone about it until the blame was flying around again.
Went in to the office for the usual arse kicking party. Asked what time the incident had happened. Then produced a print out of the machines actions at that time. Process guys were playing about with manual control. Next time it went wrong the process manager is guest of honour at the party. I was invited along so I could produce the incriminating evidence.
At one point the company brought in a consultant production engineer from our parent company, I was paired with him. He was French/Spanish, I’ve never come across anyone so laid back.
“Tony I want to try…..”
“It won’t work”
“I want to try it”
“OK on your head be it”
Crunch Bang “Oh S**t”.
“You can go and tell the fitters to fix it, I’m locking myself in the switchroom to put the program back”.
It went two ways, if I came up with an idea. He’d carry the can for me if it went wrong. It got to the stage that I could 2[SUP]nd[/SUP] guess him. Changes made before he asked for them. the classic being him collaring me “Tony I want the XXXX to do whatever”. “Have you watched it for the last week?” I walked away laughing, I’d put in the program change just to see if it would work. It did, but I didn’t tell him.
Johan and I had Carte Blanche to speed the process up. Which we did, but there were a few cock ups on the way.
He still owes me a steak dinner due to him betting me I couldn’t get a machine to do something in a set time.
The bet was I couldn’t get a machine to finish its 10 minute cycle within 2 seconds of the ideal stop time, I got it to 0.5 seconds. He cleared of to China before paying up!
Best of luck if you go for PLC’s. I’ve had 35 years of fun with them. (And a nervous breakdown). There are times when you really do have to think “outside the box”.
A favourite question used to be a DOL motor starter. It isn’t as you may think on a PLC. NC becomes NO!
