SIL3 safety relay application note

The Weidmüller SAFE Series SIL3 safety relays have successfully been tested for corrosive gases that have been in their laboratory for more than 30 days. The success of the experiment was attributed to the additional protective measures of Weidmüller electronic products, which is also sufficient to prove that the Weidmüller SAFE series SIL3 safety relays can often be eroded by salt spray for offshore infrastructure such as wind turbines or oil platforms. Certain chemical infrastructures have been exposed to chlorine or hydrogen sulfide air. This environment can cause corrosion of metallic materials, leading to premature wear of installed equipment. Of course, this situation will not only occur on components that have been exposed for a long time, even if the control cabinet does not protect the components in the cabinet from external influences. If there are no additional protective measures, such as positive pressure ventilation of the control cabinet, the contaminated air will infiltrate into the control cabinet and the control cabinet will suffer from corrosive substances such as acid, salt mist or moisture.

Suitable for corrosive environments

Joachim Janik, Product Manager at Weidmüller, said: “In particular, in a safety system, if any installation system becomes unusable due to corrosion, it poses a great danger. In the worst case, even if it is achieved The SIL rating will also fail under certain conditions. To reduce this risk for our customers, we not only introduced the SAFE series SIL3 safety relays to ensure safe use in this corrosive environment, but we also introduced the series. Safety relays have been rigorously and thoroughly tested before field application to ensure the effectiveness of our protective measures."

Weidmüller's electronics in the SAFE SIL3 safety relays are coated with a professional protective layer to ensure reliable protection of these electronic devices. Janik stated in the challenge of the product: "If we use too much coating, it will cause the performance of the SAFE series SIL3 safety relay to be reduced. But if too little, there is no way to achieve the desired protection. The tests carried out in our laboratory proved that the amount of coating we use is the most appropriate and provides the best protection for our SAFE Series SIL3 safety relays."

Application in G3 environment

The Weidmüller SAFE SIL3 safety relays were tested in the Weidmüller laboratory and were continuously exposed to corrosive gases for a full month. According to the EN 60068-2-60 standard, Weidmüller conducted a mixed gas test, also known as a group 4 corrosive gas test. However, the concentration of corrosive gas set by Weidmüller was adjusted to the G3 ISA level (American Instrument Society, ISA S71.04-1985). This level is much higher than the actual standard for the 4 corrosive gas tests.

Through this experiment, Weidmüller can simulate the environmental conditions actually encountered. Wolfgang Nietzsch, head of the Weidmüller Electronic Products Laboratory, said: “The general test period is 30 days. To ensure that everything is safe, our test period has exceeded this period. During the entire test period, our SAFE series SIL3 safety relays It is working properly. Through this functional test, it is enough to prove that the coating on the PCB is well protected against the corrosive gases. We want to make sure that our products will never have any problems under any circumstances."

After the corrosive gas test was completed, Weidmüller examined the microscope and the results showed that the Weidmüller SAFE Series SIL3 safety relay was intact. Despite the harsh test environment, corrosive gases did not cause any damage to the Weidmüller SAFE Series SIL3 safety relays. Janik concludes by saying: “We know that our customers are paying increasing attention to SIL-protected products, even in the corrosive environment of the G3 class. We have proved our success through corrosive gas tests. The SAFE series SIL3 safety relays are fully suitable for applications in this environment and are also noted in our factory declaration."