Maker Pro
Maker Pro

NPN & PNP sensors

B

b

Jan 1, 1970
0
Hello. Can anyone explain the difference between npn & pnp sensors as
used in industrial controls systems. How they work and why you would
choose one type over the other.
 
J

John Popelish

Jan 1, 1970
0
b said:
Hello. Can anyone explain the difference between npn & pnp sensors as
used in industrial controls systems. How they work and why you would
choose one type over the other.
NPN outputs pull down to the negative supply rail and drive loads that
are connected between the output and a positive supply. PNP outputs
pull up to the positive rail, and drive loads connected between the
output and the negative supply rail. If you have a lot of loads (like
a PLC input card) hat has all its inputs commoned to the negative
rail, you use PNP outputs. If the loads are all commoned to the
positive supply rail, you use NPN outputs.
 
S

Siong Boon

Jan 1, 1970
0
You can also think of it as a normally open or close configuration. Normally
logic 0 or 1, active low or high. Depending on how you interface your
sensor.
There many other ways of looking at this.
The NPN PNP terms basically come from the transistor
that is at the output of the sensor, acting like a switch.
For further information, you may like to search for topic relating to using
transistor as a switch.

--
Best Regards,
Lim Siong Boon

[email protected]
www.siongboon.com
 
Top