Some of the preventive maintenance can be automated through the PLC to even further reduce down time. The more complex our systems become, the more beneficial it is to write logic that will not only isolate failures but also indicate potential failures that may occur in the near future. This allows maintenance to change unscheduled downtime into scheduled down time. Scheduled down time, in turn reduces the amount of time down and loss of production. This is accomplished by utilizing the sensors already in place, to do testing through PLC logic to isolate where trouble is originating.
Repair is usually only a fraction of the time it takes to find the problem.
It's not uncommon to spend hours tracking down a limit switch that is bent, or a dirty proximity sensor. The cost to find the problem is more expensive then the cost to repair it. With PLCs the cost to find the problem is greatly reduced. Implementing PLC technology in the ways mentioned above could result in a 43 percent or more reduction in installation costs, maintenance and variability. And we cannot put a price on human health and well being.