Interested to Buy Any Domain ? << Click Here >> for more details...
How we will check whether the proximity, which we have is
either NPN or PNP, if no data sheet or manual or any
details is available to us ???
- 1 Answers
- 6795 Views
- I also Faced
- E-Mail Answers
Answer Posted / carl_ellis
Often identification data is printed on proximity (or prox) sensor's label but it is not uncommon for the label to damaged, missing or unreadable.
Many prox sensors are DC powered, 3 wire devices that conform to a standard wiring color code:
brown is (+) supply voltage, typically 24Vdc
blue is (-) supply voltage common or return
black is the sensor's switched output
To test a 3 wire sensor to determine whether it is a PNP or NPN type you need a DC power supply and a DC voltmeter.
Set the meter to DC voltage to a range greater than the supply voltage (typically 24Vdc), like 50/100/200/600V
The black meter probe should be in the 'common' meter socket
The red meter probe should be in the DC 'volts' socket
Connect the sensor's brown wire to the power supply (+)
Connect the sensor's blue wire to the power supply (-).
Turn the power supply on.
Ensure that the prox sensor is not triggered by presence to an object.
Connect the black meter probe to the blue sensor wire.
Connect the red meter probe to the black switched signal output sensor wire.
If the meter is connected to a PNP device, the meter will read 0V.
If the meter is connected to an NPN device, the meter will read 24Vdc.
Force the sensor to change state/output by detecting an object.
- If it is an inductive proximity switch, place a piece of metal in front of the sensor.
- If it is a photoelectric sensor, block the photoelectric beam.
- For an ultrasonic sensor or a capacitive sensor, you can just use your hand to make the sensor output. Some prox sensors use an LED that lights up when the sensor detects an object.
With an object present, a PNP device's output will change and the voltmeter readout will read 10V to 30V. This is also known as a "sourcing" device.
With an object present, an NPN device's output will change and the voltmeter readout will be 0V. This is also known as "sinking."
Another test to check for PNP:
Connect the power supply (+) to brown, (-) to blue.
Connect the red meter probe to the brown (+) sensor wire.
Connect the black meter probe to the sensor's black signal output wire.
When sensing no object, the signal output will be 10V to 30V.
When sensing an object, the signal output will be 0V.
Another test to check for NPN:
Connect the power supply (+) to brown, (-) to blue.
Connect the red meter probe to the brown (+) sensor wire.
Connect the black meter probe to the sensor's black signal output wire.
When sensing no object, the signal output will be 0V.
When sensing an object, the signal output will be 10V to 30V.
| Is This Answer Correct ? | 3 Yes | 0 No |
Post New Answer View All Answers
diff between neutral ,ground,phase , earthing and shielding?
we are using centum vp as monitoring with Dell precision work station T3600 but some times PC(s) are restarted automatically . how we can solve this problem? thanks
Decibel.
What is the use of each wire in three wire RTD
How to fix back the valve actuator stem
what is the current pay package for an instrumentation engineer having 2 years of experience in cryogenic technology???????
Punj lloyd is coming in our Jadavpur Universtiy campus for campus placement. Please send me some hints about the writtend exam. My email id is subratafriends@gmail.com
why we are not using the turbine flow meter in the steam service?
What is difference between “Fault Tolerant” & “Fault avoidance” PLC? Application where these system s are used?
my data card only does run in my mobile so how can change it that it run other mobile & computer and i can stor data in my data card
what are procedure of sox-nox calibration
what is commisioning procedure,2)what is is the main work in commisioning in the field tx to dcs, plz send me detail
Why do we floating DC in DC system.
selection of the zener barrier for the hazardeous area zone 0
What is hp & mp seperator .& what is its working principle ?
