10 Golden Tips for Selecting a Safety PLC

A Safety PLC is intended to reliably accomplish safety-related operations in order to protect people, machinery, & the environment. Unlike regular PLCs, Safety PLCs are designed to meet high safety standards (such as IEC 61508 & IEC 61511) & can carry out safety programs in the case of failure.

  1. Consider about the necessary safety integrity level (SIL). SIL levels are ranked from 1 to 3, where SIL3 is the maximum level of safety. Select a PLC that fulfills the necessary SIL requirements, or surpasses them.

  2. Verify if the PLC has received functional safety certification from safety standards bodies like TÜV or UL. By doing this, the hardware & software are ensured to meet safety standards.

  3. Analyze the environment that programs in. Select a PLC with programming software that facilitates the creation and validation of safety routines. See if there are any integrated diagnostics.

  4. Evaluate the possibilities for redundancy. To lessen the probability of hardware failures, many safety PLCs provide redundancy features. Replicated power supply, CPUs, I/O modules, & network connections are among the options that are accessible.

  5. Analyze the tests and diagnostics. A safety PLC needs to have strong self-diagnostics and testing capabilities. This covers functions like fault monitoring, watchdog clocks, and cross-channel checks.

  6. Take consideration for failsafe actions. If a failure is found, the PLC ought to enter a known safe state. For example, certain outputs can be retained in the last state or deactivated.

  7. Examine the I/O capabilities. Verify that the PLC has enough input & output capacity for the number of devices and scale of your application. One option is to use safety I/O modules.

  8. Assess the level of integration flexibility. Examine the PLC’s ease of integration with both conventional control systems and safety features. Is it capable of transmitting safety information to non-safety devices

  9. Analyze your alternatives for training and assistance. When establishing & maintaining a safety PLC system, good supplier support and training materials are essential.

  10. Simplify safety programming by properly organizing blocks, utilizing certified blocks, & selecting diagnostic measures. Avoid maintaining or bypassing branches. Choose for “zero-oriented” features such as RS flip-flops. Keep the code simple and easy to understand.