Can two safety barriers be connected in series?
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This post was last edited by liu530014416 on 2020-7-6 11:48. Can the MTL4551 and MTL5544D safety gates be connected in series? MTL4551 is a single-input single-output safety barrier, while MTL5544D is a single-input two-output safety barrier. One output of MTL5544D is connected to the MTL4551 safety barrier in the SIS, and the other output is connected to a DCS card. Is this design feasible? Honeywell’s SIS design uses MTL4551 devices together with safety barrier chassis. The company wants to allocate some of the instrument points to the DCS instead of using communication methods. However, due to the presence of those safety barrier chassis, the distributor told us that replacing 2 chassis and cards, as well as replacing 35 MTL4551 safety barriers with MTL5544D safety barriers, would cost over 100,000. In contrast, the company can purchase 35 MTL5544D units for less than 15,000. My idea is to buy the MTL5544D safety barriers ourselves and then connect one of their outputs to the MTL4551 safety barriers in the SIS. Is this feasible? Also, the MTL4551 is currently installed on the backplane, whose model is FC-GMLA16. I’m not sure whether this type of backplane supports the MTL5544D
If the line voltage of the previous safety barrier circuit can drive it, there should be no problem. Because the second one has a power distribution function and its own power supply. The intrinsically safe range in your circuit should be limited only to the first safety barrier.
This connection is acceptable; the output of MTL5544D is active, and MTL5541 should be connected to terminals 1 and 3
It’s completely fine; when receiving the signal, pay attention to whether there is a connection or not – there are circuit diagrams available on MTL