Created Date: June 13,2019

Created by: DavidH

I currently have a C0-12DRE-D PLC and I'm trying to get a measurement from the Analog outputs. I have configured by outputs as follows(apologies for the pictures if they don't size properly. I have uploaded them also):

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Now I have wired two ammeters as follows:

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I'm not getting any readings on the ammeters. My suspicion is that I need to connect 24V similar to what is found on page 3 in the manual for this PLC:

https://cdn.automationdirect.com/sta...s/c012dred.pdf

I don't want to blow anything up, so I figure it's better to ask before I do so.

Created Date: June 13,2019

Created by: DavidH

Yes, you will need an external supply

Thanks for the response.

Now this raises a second question with regards to the 4-20mA analog inputs. In the manual on the same page it shows a device wired in a 3 wire configuartion. Now what happens if I have a device that has a 4-wire configuration and it has it's own independent power supply(if you look at the attached picture this paints a clear picture with regards to what I mean). Can I just connect my two signal wires straight into an input pin and the ACOM pin?

I'm concerned about having a device that has 4-wire configuration for the input, while at the same time using the analog outputs(that have to utilize a three wire configuration according to the manual). I'm concerned that this might cause issues, since all inputs and outputs use the same ACOM pin.

Created Date: June 13,2019

Created by: Tinker

The analog current outputs on the CLCIK CPU brick are weird (though the add-on current output modules are "normal ") I think you will be ok with respect to sharing the common (which will be at "ground " potential anyway) but the weird sinking output is not always compatible with other devices.

If you budget can stand it I'd get one of the add-on modules, or possibly a signal conditioner (or personally, switch to a Do-More BRX, though that is a big hit to the budget).

Created Date: June 16,2019

Created by: Alexandru

The electrical connection you’ve made is wrong.

The analog output requires a ( resistive) load of usually 500ohms.

The only load you have is the resistance offered by the ammeter. Your schematic shows a short-circuit of the analog output via the ammeter.

You need an electrical resistor of 500ohms series with the ammeter.

As for the built-in analog outputs, I recommend you read the plc documentation. Out of the top of my head, I believe those outputs do not require external power and use low voltage (0-5v), which means lower load resistance, so you could probably use a 100ohms instead of 500. All this is to be found in documentation.

Created Date: June 18,2019

Created by: DavidH

Yes, you will need an external supply

Thanks for your advice. I just did this and it worked with the advice also recommended below.

The electrical connection you’ve made is wrong.

The analog output requires a ( resistive) load of usually 500ohms.

The only load you have is the resistance offered by the ammeter. Your schematic shows a short-circuit of the analog output via the ammeter.

You need an electrical resistor of 500ohms series with the ammeter.

As for the built-in analog outputs, I recommend you read the plc documentation. Out of the top of my head, I believe those outputs do not require external power and use low voltage (0-5v), which means lower load resistance, so you could probably use a 100ohms instead of 500. All this is to be found in documentation.

So here is what I did. I connected 24VDC in series with a 250 ohm resistor and fed that into ammeter. From there I went to DA1I(Analog Output 1) I connected the ACOM port to ground. It now works nicely and I even managed to feed the signal into a 4-20mA signal isolator with no problems.

Definitely a strange setup, but I guess if it works it works.

Thanks for all your help guys!

Created Date: December 04,2019

Created by: upstatecharley

I have a similar issue with the same PLC, the C0-12DRE-D. It is brand new from A.D. and arrived last week. I did hook it up as a sinking control @ 24v connected to a regulated 1.6A power supply with a resistive load of 600R, and although the status monitor shows the 4-20mA changing perfectly, the sink is an unchanging 0.29mA. I dropped down to 470R and down to 220R and although the sink rose to 0.39mA that of course is useless. I have set the output to a variety of levels and they are reflected on the monitor screen, it still is an unchanging sink in real-world. I printed out the book and read all the parts about this unit, I read the README doc, I configured the outputs in the software with no problem, I'm using version 2.50, I updated the firmware in the PLC the first time I hooked-up. When nothing else worked, I used a pack of 9v batteries wired in series with my ammeter to get a weak 26v. and no resistive load, and still nothing but 0.39mA passing through. Is there another hardware bug or software bug I don't know of?