AB 1746'IV16......very basic question...

[2stroke1971]

Im looking to hook up a 3 wire PNP photocell to an Allen Bradley 1746IV 16 module.

Ive watched videos about hooking up DC sensors, but they show Siemens modules being used.
They say these modules need their own 24V supply hooked to the top and bottom terminals... Im imagining the 1746IV also needs power, (meaning other than from the Chassis)

The bottom two terminals of my 1746IV are marked VDC and are jumpered together.
The diagram from AB shows DC+ to these...so power supply (+) goes here...


Question 1--where does the DC common from PS hook to my 1746 Module..
please pardon my lack of question marks, my keyboard is on the fritz!

I have the following diagram, and Im afraid to say I cant quite make sense of it.

SENSOR...

BLACK--
The video I watched on the Siemens, had the black wire from the sensor going to the input terminal of the PLC. That would be the case with my 1746IV as well Im sure.

BROWN..
to DC+24 volts..they put that wire on the same terminal where the DC24+ lands on the module itself. (im guessing if you had 16 sensors, you would run all of the brown wires off to a separate terminal block and run that back to where the DC+ for the module goes-or straight to the PS itself right..., but to keep things simple for now, lets just do it the way they showed)

So Brown to one of the bottom terminals on my 1746IV where the DC (+) comes in...

BLUE...
Now we have blue....they have that on the video landing where the DC- hits the Siemens module---I dont know where this would be with my Module.




SO in review---where does DC (-) from the PS land on my module....
It would be nice to have a Kindergarten diagram...
heres my question in a crudely drawn picture.

Thanks in advance for any input....about my DC input.... oof.
and merry xmas!

 

[nehpets]

The drawing shown is not correct the VDC should be connected to your 0 volt.


Connect the brown wire of your photcell to 24volt, the blue wire to 0volt and the black wire to your required input terminal.


Steve

 

[mechtec]

The way I see it, you will need an NPN sensor to use with
the 1746-IV16 module. For PNP sensor you would use 1746- IB16.

 

[cidchase]

If your sensor is PNP output, you need a 1746-IB16 module.
The sensor is sourcing (+ out), the module is sinking (+ in).

The IV16 is a sourcing module (-in). The module input terminal "sources" 24v, the input is active when it is connected to 0V.

The IB16 is a sinking module. The sensor sources 24v, the input is active when it is connected to 24v. In other words, the module provides the 0V, or "sinks" the signal.

The whole sink/source thig is a source of confusion and we would be better served if all mfgs would describe the sensors as "positive" or "negative" output , and the modules as as "positive" or "negative" input. Some do.