A New Year Resolution for Maintenance
As a manufacturer have you made your New Year Resolutions yet? Consider the following!
Electrical controls maintenance is often treated as a non-issue. After all, if it ain't broke, why mess with it? Let me share some real-world experience from many years of serving manufacturing customers.
We have had multiple examples through the years of why electrical controls maintenance is necessary to avoid serious downtime. If you can afford the downtime, then feel free to stop reading now.
An old boss once said to me "don't ever let me find out that my plant was down because of a $2 part". Once as an electrical supervisor, together with my electrical team, we were able to hold the attributed electrical downtime to less than 5 hours a month on a 24/7 operation for years. It is an achievable goal.
These are but a few of the highlights of a complete electrical maintenance program. There are so many more depending on your particular process. Think of maintenance as keeping your systems' engineering to its design specifications.
You need to start with an inventory of all the essential control system assets. This process is often called an installed base evaluation.
Most importantly, your drawings, programs and manuals.
PLCs, HMIs, VFDs, DC Drives, Soft Starts and Servos.
Any devices with a battery to backup the internal program.
Specialized devices and sensors.
Motors.
Transformers.
Circuit Breakers.
Old devices should be checked to find out if spares are available and even if they are, the price and expected delivery. If parts are available but with unacceptable lead times, they are candidates for your own in-plant inventory. If they are not available from the OEM, best start looking for grey market replacements. These are often 15 to 30 day deliveries so best stock up before you need it as well. If even the grey market can’t supply, make plans to replace before failure with devices that are proven but not yet at the product end cycle.
PLC programs should be backed up regularly. Operators change values stored in the PLC from the HMI as they fine tuning the machine under production conditions and create new recipes for additional products. Many PLCs store machine data such as production as well. You would hate to start from square one by loading in the original OEM program, if it's even available, or lose your important production data. If someone at least printed a copy of the PLC program out, it will take many hours of reinputting the program. If neither is available and the vendor is gone or can't supply, you are in serious trouble.
PLCs have batteries to back up the programs stored in volatile RAM. These should be changed every two years or the next time you power the machine down for a day, you may lose the program.
VFDs and servos fail from time to time. Programs have to be backup because many of them have reassigned inputs, special modes enabled and data stored in them that is critical to the way they work compared to a default factory configuration. Without a backup, many hours of programming are usually required to reprogram the device if you can figure it out at all.
Control system maintenance also includes testing systems for data integrity and calibration of field devices. Load cells, pressure transducers, flow meters and the like all need to be checked to keep your process flow and materials in compliance with its original engineering.
Don't forget the power side of your systems either. A 10-year breaker or more that fails will be difficult to find and the larger it is, the more difficult it generally is. Thermography is a necessity these days for power maintenance. Have an inexpensive IR camera on site for both electrical and mechanical troubleshooting and have a professional survey done every year to highlight any unseen problems.
This could go on until it is almost a maintenance manual but at this point, I'm sure I've touched on more than a few points for the medium to small manufacturers that have not been addressed and which have caused excessive downtime and panic.
Remember that good maintenance is just the maintenance of good engineering, so arrange for sufficient resources to do so and it will pay you back in reliability and availability of your production systems.
Remember as well at Factory Automation Pros, we don't just service downtime calls. We want to keep your downtime to a minimum and have a full skill set to help in that regard. We partner with customers who need additional resources from time to time or constantly to achieve their maintenance goals.
Steve Meredith