What is this symbol on a plc schematic?

[Helloworld25]

Hello, fairly new to plcs I’m tasked with installing a PE to a micrologix1200, in the attached picture I/14 is the PE I’m installing it’s going to allow accumulation on a flat belt. Right now the belt runs continuously with this PE it will only run when PE is blocked allowing boxes to build. I’m assuming right now the company has a jumper from + to I/14 bypassing this option. Just a couple questions what is the H1 that’s in a box on the diagram? And what is the N1 to the right mean? It’s a 3 wire sensor black (load) brown (+) blue - I haven’t opened the panel yet but I’m assuming the blue and brown run to terminal blocks? Thanks.

 

[Ken Roach]

You are correct that a typical European color code for a 3-wire sensor is

Brown +24V power
Blue DC common
Black Sensor Output 1
White Sensor Output 2

I think you are correct that you will find terminal blocks labeled "H1" and "N1".

This is a 24V system, right ?

My guess is that "H" and "N" are somebody's choice as shorthand for "Hot" and "Neutral", which would usually apply to a 120V AC single-phase system.

I'm also wondering if they mis-labeled the photoeye. I would expect Brown to connect to the +24V on the left, and Blue to connect o DC common on the right.

Maybe this system is backwards and uses sourcing inputs, which would be unusual.

Zoom out and up and see how the 24V power is distributed in these circuits.

 

[I_Automation]

To me it looks like all 3 coming off the left rail are H1, just out of focus monitor pixels make it look like N1


In that circumstance I would say the left power rail is wire H1


EDIT: Plus if the prox was DC the Blue & Brown wires are reversed unless the panelbuilder used positive as common and negative as power.

 

[Helloworld25]

You are correct that a typical European color code for a 3-wire sensor is

Brown +24V power
Blue DC common
Black Sensor Output 1
White Sensor Output 2

I think you are correct that you will find terminal blocks labeled "H1" and "N1".

This is a 24V system, right ?

My guess is that "H" and "N" are somebody's choice as shorthand for "Hot" and "Neutral", which would usually apply to a 120V AC single-phase system.

I'm also wondering if they mis-labeled the photoeye. I would expect Brown to connect to the +24V on the left, and Blue to connect o DC common on the right.

Maybe this system is backwards and uses sourcing inputs, which would be unusual.

Zoom out and up and see how the 24V power is distributed in these circuits.

H1 labeled coming from 120ac N1 is AC com . What’s weird is they have blue jumped off the 120v+ and brown as comm. the sensor is a Allen bradly retro reflective

 

[Helloworld25]

To me it looks like all 3 coming off the left rail are H1, just out of focus monitor pixels make it look like N1


In that circumstance I would say the left power rail is wire H1


EDIT: Plus if the prox was DC the Blue & Brown wires are reversed unless the panelbuilder used positive as common and negative as power.

120Vac H1 is + N1 is coming from AC common so why is blue + and brown common unless they got mixed up.

 

[Helloworld25]

H1 labeled coming from 120ac N1 is AC com . What’s weird is they have blue jumped off the 120v+ and brown as comm. the sensor is a Allen bradly retro reflective

Another thing to note is the AB sensor is a dual pnp/npn AC or DC 22-240v. In that case does it matter if blue is + and brown is - vise versa? Thanks.

 

[I_Automation]

Another thing to note is the AB sensor is a dual pnp/npn AC or DC 22-240v. In that case does it matter if blue is + and brown is - vise versa? Thanks.

AC devices don't have a polarity, but the black output wire would be switched off the brown power wire in normal AC.


If there is a setting for NPN then it would switch off the blue wire, which your schematic seems to indicate (as the other inputs are getting their signal from H1)