Machine and Process Management

Less Effort, More Gain…by Dynamic and Colorful Power Monitoring

PLC HMI fire 1Efficiency is not only about better usage or management of water/electricity resources, but it’s also about maximizing the usage of the controls and monitoring functionality/features.

I would like to address the “missed solution” in different machine and automation applications…

Do power products such as contactors, circuit breakers, motor protection, etc. typically get monitored in the automation architectures equipped with PLC’s and HMI’s?

For power products, we usually don’t know what the current status is, the fault status, service/replacement time and finding the origin of a fault in a live panel can be risky for the operator and machine debugging can be too long of a process.

Although some of the power products are equipped with their own communication modules, the high cost of the module and engineering time prevents the implementation in most applications.

PLC HMI fan 2When PLC’s & HMI’s are used in an application why not write some additional lines of code or a few function blocks in the controller side hardwired to low cost auxiliary/fault contact block and some additional pages and symbols PLC HMI Symbols 4  in HMI side to continually monitor power elements in a complicated architecture visually to follow the fault passage in a safe, cost effective and fast ways?

 

PLC HMI FB 3

 

By assigning the auxiliary/fault contact block to the AFB (Application Function Block) and accordingly linking them to the standard schematic symbols loaded in HMI library and defining graphical page/s, it is possible to cover this need.

 

PLC HMI FB 5

Advantage:

  1. Low cost dynamic & colorful power monitoring
  2. Decreasing machine debugging (down time) in power failure cases
  3. By assigning the AFB inputs to the Emergency pushbuttons, Under Voltage or Shunt Release coil disconnecting the input power, at once, is possible
  4. It is safer to follow the fault passage through monitoring or controller rather than live machine and also live panel physically.
  5. Developing and adding more parameters to PLC’s AFB & HMI pages are possible
  6. Possibility to send remote command in parallel with the manual one.
  7. Continuous and live power monitoring
  8. By counting number of open/close contacts we can plan for service/replacement of electro mechanical products as their life cycle are declared in the manufacturer specifications.

Disadvantage:

  1. More controllers digital I/O is needed (one additional input per each power product)
  2. More control wiring is needed
  3. Adding auxiliary & fault indicator contact blocks are needed for the products that embedded ones are not available

PLC HMI fire 6During my career, I was fortunate to have found opportunities that allowed me to get familiar with low voltage concepts and products besides automation.  I found that power monitoring is an ordinary concept in high end low voltage distribution applications but it’s not the same story in the automation field.  That’s why I have created/tested the Power Monitoring Application Function Block in a controller and related graphical pages in an HMI and I have received really positive feedback and comments worldwide when I have shared it.


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