Connecting sensors to a click PLC is Easy, in this video we'll connect three
different types of photo sensors, diffuse retro-reflective, and through beam; 3
proximity sensors and an ultrasonic sensor to the click PLC.
Here's what it looks like on a test rack.
Here's that click PLC and here's the three inductive proximity sensors, the
ultrasonic sensor, and the through beam diffuse and retro-reflective photo optic
sensors.
First, we'll connect the proximity and ultrasonic sensors then
we'll swap those out with the photo sensors.
The click has a power supply, the CPU, and an 8 input discrete module.
2 of the proximity sensors are intentionally
NPN and the other proximity sensor and the ultrasonic sensor are PNP.
Just so you can see how to connect the different
sensor types to your controller.
Since we have both types of sensors we need to
make sure that PLC input module can handle both NPN and PNP.
This click input module has two comments that's perfect
because we can simply connect one common to the positive voltage rail so the NPN
sensors can pull the i/o terminal low when they activate.
And we'll connect the other common to the negative rail so the
P MP sensor can pull the i/o pin on the PLC up when it goes active and that's
really all you need to remember when you have an NPN sensor which syncs current,
you need an input module that can source the current.
When you have a PNP sensor that sources the current you need an
input module that can sync the current and since click input module handles
both were in good shape.
AutomationDirect’s sensors have a diagram on a sensor or
sometimes on the wire showing exactly how to wire the sensor.
This little box as the sensors load which is the PLC and
for this sensor we see that the PLC provides or sources current from the
positive rail to the input of the sensor; So we know without even looking at the
part number that this must be an NPN sensor to sink that sourced current.
So all we have to do is connect the two NPN
sensors to this block the i/o, with the positive common and connect the two PM P
sensors to this terminal block with the ground in common, perfect.
If we bring up the click software and connect to the
PLC we can instantly see the results in the data view when I pass metal in front
of the inductive proximity sensors we see the result and when I wave my hand
in front the ultrasonic sensor we see that result.
Notice that even though the NPN sensors are pulling the input terminal low and
the P MPs are pulling it high none of that matters here all we see in the data
view is this sensors active once the sensor is properly wired you don't have
to worry about whether the signal is high or low.
To use that in your ladder code, you just bring the inputs in like
you would any other contact the NPN sensors are at address X 101 and 102 and
the P MPs are at X 105 and 106.
Could we have used the inputs that are right on
the clicked module and saved the expense of an additional input module.
Sure, this particular click has two commons so we
could have done it the exact same way.
Except now, the sensors were coming at different addresses.
We handle the optical sensors exactly the same way, we
have a through beam diffuse and retro-reflective sensor but all we
really care about is our the NPN or PNP.
The through beam is NPN and the other two are PNP, so we'll connect the NPN
sensor to the i/o block with a positive common and the PNP sensors to the i/o
block with the negative or grounded common.
I replaced the other sensors with these so when we bring up the data view
we get the exact same result.
Mechanical switches can be connected as either
sinking or sourcing.
AC proximity sensors can also be used for sinking or sourcing
just make sure you have an input card that can handle the AC voltage.
If you have any questions please don't hesitate
to contact automationdirect's free award winning tech support during regular
business hours.
they'll be happy to help and don't forget the forum's, there are
lots of folks there that love to share their years of experience
just don't post any tech support questions there automationdirect's
support staff doesn't monitor the forums on a regular basis.