Wiring 3 Wire DC NPN and PNP Sensors

[@mumbles1justin]

Im still a little unclear if i need NPN or PNP sensors for mosaic M1. I ordered NPN sensors but they haven’t arrived yet and still researching to verify I have the correct sensors before they arrive and I hope them up.

[@ACCautomation]

Hi Justin, The Mosaic M1 has 8 PNP (active-high) digital inputs. Here is a diagram that shows the NPN and PNP sensors. accautomation.ca/heres-a-quick-way-to-wire-npn-and-pnp-devices/ You should be using PNP sensors for the input to the Mosaic M1 controller. The actual transistor in the diagram will switch the +24 VDC signal to the input point. (PNP) Regards, Garry

[@mumbles1justin]

Thanks Garry! That diagram cleared everything up.

[@chrisbarnett6982]

In an NPN setup, what is the voltage measured from the output wire to 0V when the sensor is not high? I am thinking that there are two options - the first is that it is at full 24VDC, so that it is at the same potential as the input point and no current flows. Second option is that the BJT completely opens the circuit and the reading is 0VDC, but only because there is not a continuous path to either 0VDC or 24VDC. I am leaning towards option 2, but I don't know. Any idea?

[@ACCautomation]

Hi Chris, You would measure 0 volts on an NPN sensor that is activated between the sensor output (Black) and 0 Volts (Blue). 24 Volts would be measured on an inactive NPN sensor. Remember that voltage is the potential to do work. If a sensor (switch) is open then the potential exists and a voltage can be read. When the sensor switch is closed there is no potential so no voltage is read. (0 Volts) I hope this helps you out. Regards, Garry

[@rajsoparia9886]

Garry, U R AWESOME!!!!

[@ACCautomation]

Hi Raj, Thank you for the comment. I appreciate it. Garry

[@R945-l6f]

Hmi showing 200micro meter output for a field installed ideal 3 wire proximity sensor installed on a pump shaft what might be the problem, how to diagnose a faulty sensor by using a multimeter

[@ACCautomation]

Hi R 945, You can measure the output lead and 0v lead for voltage on your multimeter. As the sensor has items in front of it or not, you should see the DC supply voltage or 0 Volts. Regards, Garry

[@enverismail6864]

What im not understanding us how are you getting you BJT to switch with a positive voltage

[@enverismail6864]

I'm talking about NPN transistor now. I believe it ONLY works with negative voltage

[@ACCautomation]

@@enverismail6864 Just about every video has an associated website page with additional information. Here is the link to the website page. accautomation.ca/wiring-3-wire-dc-npn-and-pnp-sensors/ This may have the answers to your question. Let me know how you make out. Regards, Garry

[@jong3161]

From your power supply

[@ACCautomation]

@@jong3161 Most items are referenced with respect to the common point of the input of the PLC. Regards, Garry

[@analie1372]

Hi how to connect three sensors to a control system and power source??

[@ACCautomation]

Hi Analie, Can you give me a little more information on the sensors and plc that you are using? (Sensor model/type and PLC model and input type) Do you want the three sensors wired in series to the input, parallel to the input, or all individually to separate inputs? Thank you, Garry

[@analie1372]

@@ACCautomation all three should have same input at the same time or else it will equivalent to false. So they should the connected with each other. It's a three wired sensor

[@ACCautomation]

​@@analie1372 The following website will show the connection of 4 sensors in series to an input. This is for the protection of a die. www.wintriss.com/wcg/knowledgebase/122012.html You did not mention NPN or PNP but this diagram should give you an idea of how to wire the circuit. I hope this helps you out. Regards, Garry

[@analie1372]

@@ACCautomation thank you it's a great help 😊

[@ACCautomation]

@@analie1372 You are welcome. Garry