Basics Training
The more we adapt ourselves to the new tools used in troubleshooting modern control technology, the more we forget how to do it the old way. Ya know, when the grumpy old relay logic board or weary wire nut acts up? Laptops, cables and software have pushed aside the good old-fashioned, sleeves rolled up, hands-on, hard-thinking style of troubleshooting. We have become so entrenched in the PLC world that we tend to target the PLC, even when the PLC has nothing to do with the technological problem.This dilemma might call for a refresher course in what I refer to as the 5T method: Tap, Tug, Tighten, Test and Twist.
Or just getting back to the basics.
Let’s take the following scenario, for example. Your operation is running along fine, and suddenly, the product stop cylinder on your conveyor quits working while every other segment on the machine continues functioning as it should. Since the overall system is controlled by a PLC, you send your tech guy scurrying for his laptop. Meanwhile, you stand guard watching the little red LEDs on the processor blink while trying to remember what is what.
Then along comes your tech jogging with cords dragging on the floor behind him. Oddly, the laptop is already open, and the software program is up and running. This is not always because we are prepared. Rather, sometimes it’s because he just took the computer off of the stubborn overhead door that was acting up.
Yes, even garage doors have computers now.
About six minutes later, your cable is plugged into the processor, and the tech clicks open the ladder logic on the screen. He opens one page but it’s not the correct one. Another few minutes go by, and the accurate screen shows the circuit involved. You watch the live action on the monitor and see the circuit that controls the product stop send a signal towards the solenoid valve. It’s now been 10 minutes, and more than a 1,000 loaves of bread had to go somewhere other than to packaging. Long story short, you chase for another couple of minutes only to find that a wire nut fell off a connection directly at the valve coil. You put the wire back together, tighten the nut and off you go.
Never happen to you? Yeah right!
That’s because sometimes we allow our computer to think the problems through rather than us taking the time to remember our roots and get ourselves back to basics. If this same scenario happened 20 years ago, you would have automatically spent your first five minutes right at the point of the problem and very likely conducted the 5T method. If you did, this same problem would possibly have been solved inside that first couple of minutes.
We have to remember that most, if not all of the components that actually do the work on the machines today, are no different than they have ever been. The main difference is back in the control panel where we dropped in computerized controllers in place of most of the relay boards and plug in timers is old.
In addition, the PLCs we use today are very reliable. They either work right, or don’t work at all. It’s rare to find that a computer has “adjusted” its program without human intervention. With that in mind, it might be best to spend your first few minutes in a 5T mode. Even in a PLC environment, there are many electrical components and wire connections between the brain and the brawn.
There is always an opportunity to Tap on an output relay to make sure it is seated, to Tug on a wire at a contactor to make sure it is tight and to Tighten a screw in a terminal strip to assure you are holding the wires. Grab your old school Wiggy, Simpson or Fluke and Test voltage. Also, never pass up the opportunity to give a Twist on that lonely wire nut even though it looks in place.
The time is right to step back and think about how we used to troubleshoot and realize it still has a place in our high-performance, high-tech baking plants. Getting quality product through the process and on to the truck without error has probably never been more important than it is right now, at least not since the last economic depression.
With the historically high cost of commodities, fuels and labor, and the tightening of capital spending, production efficiency is your No. 1 money maker. To ensure that this happens, you need to reduce the time that machinery is out of service. This responsibility is solely in the hands of the maintenance manager and the team of techs and mechanics.
Troubleshooting problems with a sense of urgency makes up the center of this effort. The best preventive and predictive maintenance executions can lead to better efficiencies, but even the best precautions will never eliminate the odd occurrence where something just breaks or shorts out. It is at those moments where the old school mentality could pay off. Think about spending a few minutes with each of your techs and mechanics and go through some “Basics Training.”
Who knows? Maybe you can teach a new dog some old tricks.
Jeff Dearduff
j.dearduff@comcast.net
