Could some expert please explain this?
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Can the EJA120 differential pressure transmitter be connected directly to a Siemens PLC?
Is it possible to connect the EJA120 differential pressure transmitter directly to a Siemens PLC? This statement is quite vague. If you look at the principle by which PLCs process data, it will become clear!
In principle, it’s possible. There are two scenarios: 1. It’s no problem to feed the pressure variation signals from eja into the PLC; 2. It’s also no problem to feed the differential pressure signals that are not from eja into the PLC. The main issue is that I’m not sure exactly what aspect you’re referring to with your question. I think as long as the PLC can handle analog signals, that’s fine.
It is acceptable if the cards are connected to transmitters only (powered by a single power source); it is not acceptable if the cards have both passive and active components, as although the display may function normally, interference between channels is very likely to occur. It is generally required that all analog signals entering the PLC be equipped with isolation converters; otherwise, reliability will **decrease**. Many PLC analog cards are grounded together, so only by using the same power supply can interference between them be avoided.
Any transmitter for a two-wire analog signal can be connected to the signal terminals of the analog input cards with loop power supply function in DCS or PLCs – this is an industrial standard. I’m not sure what the real intention behind the original poster’s question is