How do pnp sensors work

When used in a traditional relay type control circuit, it is normally possible to use either the PNP or the NPN type of sensor as shown below. PNP sensors tend to be more commonly used. Traditional relay type control circuit; Use with a programmable logic controller PLC. When selecting a sensor to be used with a PLC, it is very important that the sensor matches the type of PLC input card to be used.

Grey case: Open the ED case using a small flat head screw driver pushed into the sides of the case which connects the lid to the case base and find the jumper with PNP and NPN next to it.

Related FAQs. What are Inputs and Outputs? Related Products. Related Range. Contact Us. Email: [email protected]. Keep in touch. Stay up to date by joining our email newsletter. If you are human, leave this field blank. Your Items. See All Products. Industrial Edge Controller. The typical value of a pull-up resistance is 4. In the case of Yoctopuce modules, you don't need to add an external resistance: pull-ups are embedded in the modules.

The pull-up principle. The advantage of NPN outputs is the possibility to choose an arbitrary signal voltage. However, as these modules cannot provide more than 5V, you'll probably need an external power supply to power your sensor.

What you have to do is:. It even has a pulse counter enabling to precisely count the number of transitions happening in a given time frame. It can count tens of thousands transitions par second. That's why one can use it to count objects passing ahead of a sensor, even if they are very fast, but one can't use it to know exactly when an object is front of the sensor. As with the Yocto-IO , you need an external power supply for your sensor.

There as well, you need an external power supply. So early solid-state sensors were more likely to use NPN transistors in their switched outputs, so they were load-sinking. The machine bed was connected to ground.

When a metal part, such as a piece of sheet steel or a stamped metal part, made contact with the whisker wire, the circuit became grounded and the relay pulled in. This was a load-sinking connection. NPN control circuits. With PNP, if a load wire shorts to ground, the short can be found relatively easily because there may be visible damage due to the higher-than-normal current that would flow in the absence of a load impedance. An unprotected, unfused sensor may also have its output blown.

If the PNP sensor has integrated thermal, latching, or pulsing short-circuit protection, the existence of a short circuit condition on the load wire will be apparent at the sensor. In the case of a short to ground in an NPN circuit, there is no abnormal current flow; the load is simply pulled in regardless of the sensor state. This could prove to be somewhat difficult to detect, because if the sensor associated with the grounded load wire is examined, it will be found to have no fault.

In the modern industrial world, NPN is considered more common and popular in the Asia-Pacific region simply because of legacy practice and the desire for backward-compatibility. Nice website and good explanaition, however I still dont know in which situation should I use each other. They have diferences, but why should I use one instead of the other? What do I gain using one or the other? Which one is best?