Newbie with wiring ?

[woodshew]

I pulled some SLC 500 out of some producion machines. I wired up an input with a 13 V dc charge. I set the program to fire 4 outputs on the input but there is no votage coming from the outputs. They do change to 0 volts so I know something is happening.
I suspect that the in voltage is to low but the sticker on the side of the SLC says that I am in the range.
Any hints?
Hugh

 

[PLucas]

woodshew,

a couple of questions for you

1. is the input LED lighting up?

2. are the output LED's lighting up?

3. Is the common terminal of the input module connected to 0v DC, or for that matter is it a DC digital input module?

4. have you wired your relay output module correctly, +v DC connected to one terminal, possible L and the return from your 'load' to the M terminal or 0v DC?

Maybe a bit more information and we could possible answer your query to your satisfaction.

I was not going to jump in and answer this question as I thought 'God this really is BASIC', But then I thought we all have to start some where, you can't run without first learning to walk and learning to crawl comes before that.

Paul

 

[john paley]

Is it a sink or source input card??

 

[akreel]

woodshew,

a couple of questions for you

1. is the input LED lighting up?

2. are the output LED's lighting up?

3. Is the common terminal of the input module connected to 0v DC, or for that matter is it a DC digital input module?

4. have you wired your relay output module correctly, +v DC connected to one terminal, possible L and the return from your 'load' to the M terminal or 0v DC?

Maybe a bit more information and we could possible answer your query to your satisfaction.

I was not going to jump in and answer this question as I thought 'God this really is BASIC', But then I thought we all have to start some where, you can't run without first learning to walk and learning to crawl comes before that.

Paul

5. Do your inputs/outputs change state when you look at them online in RSLogix?

 

[rogerhollingsworth]

Wiring

It would help if you were to give information on your PLC and include the cat# of the card in question.


-Did you confirm your 13vdc source?
-Is the polarity correct for the type of card you are using?
-Do you have a blown fuse in the module?
-Make sure your PLC can see the card.
-Is your output data table expanded to include this card?
-Do you have a rung programmed?
-Can you go into the data table and manually turn on the bits of the module and if so does the corresponding lights light up on the module?


Roger

 

[Eric Nelson]

I have a strange feeling we'll never get the answers to these questions...

beerchug

-Eric

 

[john paley]

Woodshew has figured it out for himself, perhaps??? Naaaahhh!

 

[jimtech67]

Just a shot in the dark. Maybe woodshew thinks the input voltage supplies the outputs??????????????

 

[woodshew]

Answers

Hi all,
Thanks for the responses.
The cat# is 1747 L30C.
I have wired the 120VAC to the proper terminals and have joined the PWR Out com to the DC Com and have a wire on the PWR Out +24 DC. I used it to test all the inputs and the lights do come on. I wrote a simple program to fire the outputs and they all work properly. I just don't read voltage on the outputs. I am trying to find manuals for this thing.
Thanks for the tips

 

[Eric Nelson]

First off, here's the manual:

http://www.ab.com/manuals/cp/1747621.pdf

Second, it looks like you don't have power TO the outputs, and therefore, won't have power FROM the outputs. The L30C has relay outputs, which can be thought of as simply a switch.

Here's a connection diagram (page E-37 of the manual)

[attachment]
beerchug

-Eric

 

[woodshew]

Thanks for the tips. Now I can get started!

 

[Tom Jenkins]

Back to basics....

Woodshew and others: this is a common problem for those beginning PLC systems. The solution is to sit down and go through the process step by step. It seems like more time, but in the end it saves both time and energy.

First, create your point list showing all the PLC I/O, their voltage levels, and the sensor or actuator they are wired to. Include spares.

Then make electrical schematic drawings of the system showing the PLC inputs and outputs. I like to use good ol' JIC ladder diagrams for that. It then becomes obvious if you don't have a complete circuit for power into and out of each PLC I/O point. Very few PLC's have I/O that generate their own voltage. (They are dry contacts or pasive devices to continue another thread!) This will also show if you are mixing commons or neutrals, or have different voltages on the same common, etc.

 

[akreel]

Re: Back to basics....

Woodshew and others: this is a common problem for those beginning PLC systems. The solution is to sit down and go through the process step by step. It seems like more time, but in the end it saves both time and energy.

"Follow the chain!" - Tom Jenkins