Hello guys, I have a little dilemma here. Originally, this layout was made with one sensor in mind. However, it was discovered there's a better way with two sensors. Original circuit has one PNP NO Inductive proximity sensor. Wired to a relay, which controls the motor, connected to a pwm controller. Attached below is the circuit. Blue wire on the sensor is the signal wire. Original function was for the sensor to turn off the motor when the tube gets full of coins. The thing is, once the coins are at the top of the tube, the motor will turn on only to feed a small number of coins, a trickle if you will.

I'm thinking in order to avoid that, a second sensor can be added at the midway point, it will start the motor, until the coins reach the top sensor, at which point the motor will stop feeding coins. I have no idea how to add the second sensor to add that function. I added little positive and negative "hubs" for future expansion. Appreciate any and all help =)
Sorry for my crappy ms paint skills, I'm new to all this!

 

Welcome to AAC.

It would be very helpful if you could explain the application and the mechanical parts. I fear it sounds like you are going down the familiar path of patching up something that really needs to be completely reformed.

 

Certainly this is a CLASSIC problem, and the standard fix is also classic.
That is a second sensor switch to start the motor when the supply reaches some low point, and then threlay stays electrically latched until the level reaches the full point.
That is identical in circuits to the start button/stop button scheme that is also a classic circuit.

 

Can you link to a datasheet of your sensor? I have used thousands of inductive sensor and never saw a 3-wire DC proxy where blue wire was the output.

 

The application needs one N.O. switch to latch the rely and one N.C. switch to release it. That might be a bit tricky with 3-wire proximity switches.

 

Can you link to a datasheet of your sensor? I have used thousands of inductive sensor and never saw a 3-wire DC proxy where blue wire was the output.

I colored it blue for clarity, for me. I don't have the physical switch. Sorry about that.

The application needs one N.O. switch to latch the rely and one N.C. switch to release it. That might be a bit tricky with 3-wire proximity switches.

I was thinking of using a two wire inductive sensor but I don't know how to wire it in conjuction with the pwm controller.

 

Welcome to AAC.

It would be very helpful if you could explain the application and the mechanical parts. I fear it sounds like you are going down the familiar path of patching up something that really needs to be completely reformed.

Here's the actual project, I just get nervous on the internet when I have to say it's for bullets
He puts the circuit design in the last couple of pictures, link here. He also has a video here.

But basically, like some people have said in this thread, it's basically gonna be a latched relay setup with two inductive sensors. I'm just having a hard time trying to figure the wiring, especially since this has a pwm. I appreciate any and all replies, thanks!

 

The motor control will be STOP/START, and it should not be affected by needing to do other than switch the motor drive on and off. The motor speed control and the stop/start control should not be the same.

 

OK, I see one problem which is that while the functions of the two switches in the circuit are opposite, the operation of the two inductive sensors are the same. They are both "PNP Normally Open devices.
So the simple solution will be to have each switch control a separate small relay. When the top switch is triggered it will operate the relay (with normally closed contacts,) which will open the "STOP" circuit. When the lower switch is released because the stack has fallen below, the second relay will release, and it's contacts (Normally Open) will trigger the "Start" circuit. As the stack rises, the start control will be released, but because the "start" function will remain active because it is latched.

Note that using this scheme will require a separate "OFF/ON" switch for when the system is to be off.

If folks can't grasp the circuit from the description, and if they are not familiar with the concept of a latched relay start/stop function, "Sorry about That."

 

I colored it blue for clarity, for me. I don't have the physical switch. Sorry about that.

Just for future ref, the current colour standard for Prox SW etc is:
Blue = Neg
Brown = Pos
Black = Output

 

OK, a PNP open collector output will "pull up" when triggered, I think. So the relay coil will connect between negative and the output lines.