Sensor question

A 2-wire sensor with one NO contact is actually a switch.

A 3-wire sensor with a pair of NO/NC contacts is actually a changeover switch.

Who knows what they are connected to <rhetorical question>?

PWSlack:

It is time pressure so I cannot start right at the first. It does not mean about switch. Let's consider it as capacitance sensor.

When we connect 24vdc 2-wire sensors, is that meant we connect negative point to the sensor then the output of sensor connects to the load (here means the coil, relay...). Is it possible to connect directly the sensor to power source?

The same question to 3-wire sensor.

Regards,

Hien

hope this helps. (2-wire DC sensor as NO contact:blue to negative, brown to coil A1, coil A2 to positive.) (2-wire DC sensor as NC contact:brown to negative, blue to coil A1, coil A2 to positive.) (3-wire NPN sensor:brown to positive & coil A2, black to coil A1, blue to negative.) (3-wire PNP sensor:brown to positive: black to coil A1, blue to coil A2 & negative.)

So the 2-wire sensor has three wires, and the three wire has 4? [Confused of Dodman's Lane]

Please read the manufacturer's installation instructions for the device in question. If there isn't time to look at the instructions, then there isn't time to wait for a reply on CR4.

RTFM. I concur.