A pressure transmitter can be connected to several devices
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There are 3 compressors in the system, with 2 in use and 1 as a backup; the exhaust gas is directed to the same air storage tank. It is now necessary to monitor the pressure in this storage tank after the compressors discharge their gas, and if the pressure drops, the compressors should be started. The manufacturer said that 3 transmitters need to be installed at the gas cylinder location. May I ask: Is it possible to install only 1 transmitter, with the signal sent to 3 PLC cabinets? If possible, how can it be achieved? (Note: The manufacturer has provided 1 PLC control cabinet for each compressor.)
Yes, it’s a price/current signal distributor that divides the signal into three parts and sends them to each PLC. The control pressure can be set; for example, if the pressure is set at 1 MPA, pressing the start button activates the first compressor. When the pressure doesn’t reach that level, the second compressor is activated, which achieves a constant pressure control effect
If a voltage signal is connected in parallel to the modules of the three PLCs, and each of the three PLCs sets different start pressure conditions for the corresponding compressor, it is theoretically possible to do so. I haven’t tried it, so please correct me if I’m wrong.
Personally, I think three units would be better, so as to enable separate control of the start and stop for each compressor
It is best to use 3 pressure gauges to implement a two-out-of-three redundancy system for monitoring the pressure in the air storage tank at the compressor outlet; when the pressure drops, the backup unit is activated. Why not use three compressors and instead go with a single PLC for centralized control? Or the system is also redundant, wouldn’t that make the reliability even higher? !