# 120vac inputs



## Cow (Jan 16, 2008)

I really like the Click for basic stuff. 120v inputs are very common for plc's. If someone doesn't make one with 120v inputs they need to pull their head out....

http://www.automationdirect.com/adc...lers/CLICK_Series_PLCs_(Stackable_Micro_Brick)

The software is super easy to use and free to download.


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## JRaef (Mar 23, 2009)

The A-B Micro 800 Series PLCs have versions with 120V inputs, and the programming software is free to download off of the internet.

http://ab.rockwellautomation.com/Programmable-Controllers/Micro830#/tab5

It's not "special" for companies that market primarily to the North American market, then secondarily to the rest of the word. But for companies that make their products primarily for the rest of the world, then secondarily for North America, 120V inputs are expensive to develop and maintain based on what they consider to be a relatively low volume. Nobody outside of NA uses 120V for controls. People in IEC countries used to use 230V for controls, but recent changes in safety requirements have them all using 24VDC now for everything they can, so that includes PLCs.


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## Jlarson (Jun 28, 2009)

Yeah IDEC is pretty sparce in the 120V I/O department. I think they have an 8 point 120 input module for the micro smarts now. Stuck with RO's for 120 outputs.


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## nolabama (Oct 3, 2007)

Alright then. I am learning. Thats good. 

Relay outputs. What does that mean? The output is specifically for a relay coil?


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## JRaef (Mar 23, 2009)

nolabama said:


> Alright then. I am learning. Thats good.
> 
> Relay outputs. What does that mean? The output is specifically for a relay coil?


No, it means there is an actual tiny relay inside the I/O card wired to the terminals, as opposed to a solid state output, transistor (for DC only outputs) or triac (for AC outputs). The problem with using solid state outputs is that they can have "leakage" that can cause issues, and if they are switching anything inductive, like a coil, their current rating is very very low because of inrush and inductive kickback. Relays provide you with a real air gap isolation in the circuit and usually a little more current capacity. But solid state outputs can be much higher density, much higher speed and they don't wear out if you have a high duty cycle.


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## bill39 (Sep 4, 2009)

nolabama said:


> Alright then. I am learning. Thats good.
> 
> Relay outputs. What does that mean? The output is specifically for a relay coil?


A PLC "relay output" means the PLC's output point is a set of dry contacts (usually N.O. only). You would have to check the spec's on the I/O module to find out the rating, but usually it can handle 120VAC and maybe 2-5 amps.


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## Jlarson (Jun 28, 2009)

If you are going to be doing any LED pilots, beacons or stack lights with the outputs use relays, triac modules leak enough to light them up.


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## nolabama (Oct 3, 2007)

Need it to close a contact and light a pilot light.


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## Jlarson (Jun 28, 2009)

Here's a Click with 6, 1 amp relay outputs and 8 ac inputs.


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## nolabama (Oct 3, 2007)

That is going to do more than I need. Thanks guys.


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