What is plc Redundancy
What is PLC redundancy? and Do we really need PLC redundancy will be covered in this post. What various forms of PLC redundancy are there? Redundancy is the provision of a backup control system in the event of a fault, in engineering speak. This will increase the process control system’s dependability and shorten downtime in the event of a failure. Every sector has a unique definition of redundancy. For the process control system, redundancy is typically necessary for the following reasons:
  • To ensure the safety of the surrounding area’s workers and the equipment
  • To minimize downtime when a failure condition exists.
  • To continue carrying out the crucial process without interruption
  • To avoid damaging important machinery or equipment

Types of PLC redundancy

  1. Cold Redundancy
  2. Warm Redundancy
  3. Hot Redundancy
Redundancy levels can be divided into three categories: Cold, Warm, and Hot Redundancy.

1. Cold Redundancy

Where the process is not crucial, downtime, and human operator participation are allowed, cold redundancy works well. For instance, if a pipe coating equipment malfunctions on a pipe finishing line at a steel company, an alarm will go off alerting the operator to the issue. The operator recognize the alert, asks for the failing unit to be repaired, turns on the other unit, and then begins operation. Due to the plant’s multiple parallel units, in this example, the PLC failure is not a huge concern. The identical spare PLC or components that make up this cold redundancy can be quickly programmed or changed in the event of a malfunction. A heated and hot redundancy will be a better choice for processes that are more important. Also check: Virtual Reality Market Size, Trends, Research 2023-2028

2. Warm Redundancy

The warm redundancy design style is ideal in situations when timing and response to a breakdown are crucial, but a brief outage is still tolerable. For instance, if a RAL in a bag filtration system malfunctions, it is possible to disable that chamber and perform maintenance work. There must be a reasonable amount of time before the product begins to decay or suffer damage, depending on the method. Within this time, the maintenance should be finished and the process should be back in operation. Similar to this, warm redundancy systems typically run in stealth mode. The same software and IOs are shared by two identical PLCs. The primary PLC is one of the two, and the secondary PLC is the other. The control of the automation system is removed and uninterrupted functioning is provided when the secondary processor does not receive the heartbeat signal from the primary processor. To prevent conflict, these need an arbitration circuit to handle the sensor and actuators. Because transition may require several programme scans to be finished, there may be a risk for glitches and bumps.

3. Hot Redundancy

The design of warm and hot redundancy is similar, but hot redundancy allows immediate process correction when a problem is recognised. For instance, if a primary controller for a conveyor fails in a mining or ore operation, a backup controller should take over right once to prevent any transfer delays. To enable constant messaging between processors and access to shared data, the PLC programming software and hardware synchronization must be strong. Data can be shared between processors or accessed through a networked common database. In either case, the secondary process needs to be aware of every logic cycle that the initial process went through. This article in the Truoi News must have given you a clear idea about what is PLC redundancy and types of PLC redundancy. Also how it can help industrial automation industry to achieve their goals faster and more efficiently.

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