capacitive prox sensor

Thread Starter

clark.kent156

Joined Aug 17, 2019
38
Need some help. This is how my setup is currently. NPN prox. I want to actuate the solenoid. In this configuration, I can put detectable object near the sensor, the light blinks on, nothing happens. To test, I connect the multimeter, red lead to sensor signal, black to ground. My belief is if no object near sensor, reading should be 0v. Object near sensor, 12v, sensor is NO. But, in my case, reading is 12v with no object, and with object, just over 11v. So now I'm confused what happening. It never does actuate the solenoid. What am I doing wrong here? prox sensor setup.png
 

Yaakov

Joined Jan 27, 2019
3,155
An NPN sensor gets pulled low when it is "on". That is, when nothing is being sensed the output will be at the supply voltage but when it senses something, the output will be pulled down to 0V.

This is the opposite of how you seem to be thinking about it, which would be correct if it was a PNP sensor.
 

AlbertHall

Joined Jun 4, 2014
11,311
The sensor output is wired direct to the solenoid and there is every possibility that it cannot supply enough current for that.
Also the relay has only two pins connected and so cannot be switching anything.
 

Thread Starter

clark.kent156

Joined Aug 17, 2019
38
An NPN sensor gets pulled low when it is "on". That is, when nothing is being sensed the output will be at the supply voltage but when it senses something, the output will be pulled down to 0V.

This is the opposite of how you seem to be thinking about it, which would be correct if it was a PNP sensor.
ok. after a little google, i can see you are right. can't believe i got that backwards. can i simply rewire it to be pnp? or do i need and actual pnp sensor?
 

Thread Starter

clark.kent156

Joined Aug 17, 2019
38
The sensor output is wired direct to the solenoid and there is every possibility that it cannot supply enough current for that.
Also the relay has only two pins connected and so cannot be switching anything.
I actually wired it this way according to a post i did here recently. so, should i be wiring this thru the other contacts on the solenoid then?
 

MaxHeadRoom

Joined Jul 18, 2013
23,111
The automotive relay is 85 & 86 for the coil and 30 & 87 N.O.
The prox should be picking up the coil and the contacts switch the solenoid, you do not appear to have it wired this way.
 
Top