Fire control room, if you want to display, control the water level of the pool, the signal needs a few lines
Not always。 The most common should be two lines.
The measurement of water level in a water tank is a liquid level meter with two wire 4-20mA signal output. These two lines are both signal lines and communication lines, and 24V power supply. The current signal is to the acquisition unit of the fire control room, such as the PLC of the AI, and then displayed on the computer screen or directly into the instrument display. The liquid level displayed is always corresponding to the water level of the pool, and the control room can know the actual level of the pool at any time.
If it is only the amount of switching, for example, the water level gauge installed in the water tank is only a high and low switch signal output, then it is three lines or four lines. If it is two switches, then high two lines low two lines, if it is one of the high and low switching signal, then three lines, public ground + high + low.
