Problem of splitting the pressure transmitter signal in two
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Help: There are two places where the signal from the on-site pressure transmitter is needed. Can a 1-in-2-out signal distributor be used? Both locations specify 24V active supply; will there be any issues with the power supply on the transmitter side after connecting them to the distributor? Does the signal distributor require additional power?
The approach we take in such situations is to use a two-way safety barrier, supply power to the safety barrier separately at 24V, and have both ends accept only 4–20mA signals, with no power supply provided. For specific details, refer to the wiring schematic in your distributor’s manual
The signal distributor requires additional power supply.
Why is it so troublesome? The signal distributor requires power supply, as well as being used to supply power to the field transmitters. The distributor outputs signals to the area where you use it; passive signals are used, meaning no power distribution is required
In non-explosion-proof areas, a one-in-two-out distributor should be used; the power supply for the transmitter is usually provided by the distributor
Well, it seems there are instruments that support multi-variable output; the first output provides pressure, and the second output also provides pressure. This can be achieved using a signal distributor supplied by the manufacturer, right?
There are two solutions: one is to use the DCS’s internal configuration software to make the second signal value equal to the first signal value, that is, to have the second station read the signal from the field transmitter. The second approach is to use hardware solutions, such as adding a signal distributor or a two-input one-output safety gate. Since signal conversion and distribution require additional energy (the signal card contains circuits for signal amplification and distribution), separate power supply is needed, and the wiring process involves one or two extra steps.
A one-in-two-out safety barrier is easy to set up; remember to place the safety barrier on the side of the system with a higher security level. For example, if you are working with both SIS and DCS systems, place it on the SIS side – there’s no difference in terms of connection to ordinary transmitter circuits
Isn’t this just one in and two out? One power supply is sufficient at the site; by using the distributor you mentioned, it’s possible to supply power to two locations from there. It’s better to use a safety barrier for extra security. Also, you can send signals directly on DCS. All of them are fine
A safety barrier with one input and two outputs solves the problem; the power supply can provide power independently