Micro820 Analog Output Issue

Hi all,

Playing around with this controller for a future project.
Background: Micro 820 with 1 analog voltage output.
Discrete on/off to enable an ABB VFD and also give speed reference (0-10).

Currently when drive is enabled I goes straight to 60 hertz. The analog input and terminal is set correctly on the VFD.

In the attached you can see how the Micro 820s scaling converts the units 0-4028 to 0-10 for the drive and it should be out puting 3 volt DC--It does not.. Does this appear correct? Oddly, when you go from speed reference to ground it's 9 volts (still not 10) but 0-10 to the 24 negative you get 0. I have had issues with this controller before (stuck digital input--still on and this unit has never been in service) I'm just wondering if there's an issue with the analog out.

Also the Micro 820's output terminals have been wired correctly with 24vdc going to the strip and the neutral.

FYI--I move the analog out on the drive to AI2 and set the drive up for the terminal and now it doesn't go to 60 hertz, just to 10 hz which is set up to be the minimum freq. So still not getting the analog out from the PLC terminal strip.

Check the voltage with no load connected. Make sure you can vary it by changing the output data. Check to make sure that the VFD analog input is set for voltage and not mA. That may require a dipswitch or jumper setting.

These are just general suggestions, I have no experience with that particular PLC and you didn't specify which ABB drive you are dealing with.

There is no voltage connected or not; It's an ABB ACS355.
No matter what raw count I have the ref set to before it's scaled there still is no voltage coming from the controller despite the fact it's changed on the output instruction in the controller variables window (same as monitoring controller tags with Rs5000, etc).
I believe the drive is set for voltage, but either way it's not receiving any because I should be able to read it.
I saw one website where they have the Raw and the scaled reversed from what I have in the instruction--that doesn't seem to make any sense but i haven't reversed it to try and see if it would work.

You need to make sure the ground of the PLC and VFD are tied together, (I believe your scaler (The output should be 4008))

Is the PLC wired like the Picture, and you have the vfd speed control referencing the correct analog input.

It should work.

Damica it is wired like the picture. The only ground currently on the vid are the 3 phase. I haven’t landed a ground on the drive terminals. Even then I would think you still should have 0-10 coming from plc whether the drive is grounded or not, correct?

you need to change the max(Output) on your scaler also, I don't think it will work the way you have it in your picture.

damica1 said:

you need to change the max(Output) on your scaler also, I don't think it will work the way you have it in your picture.

Click to expand...

How do you mean? The variable is wrong (10)? Or what am I missing?


Thx

I think your 10.0 is correct, but try setting the output MIN to 5.0... if its wired/working correctly than you should have 5 as the output and you should be able to read it

Also... just have to ask, is the PLC in Run?

EDIT: maybe the issue is according to your first DOC post you have TIA Portal running

genius,

Yep, it's in the run. The drive enable (_IO_EM_DO_01) goes true with my maintained switch.
I'll try the 5.0 but i imagine this is only for test purposes, correct.

I just went back online with it; my scaled output after converting to a word from Real and I referenced to the AO, is 4 and I have nothing on the 0-10 analog terminals.

I'm thinking the analog output is bad just as one of the digital inputs are.

If you want email me the program and I will download it to one and let you know if its your PLC or something else and yes the 5.0 was just for a test

EDIT email [email protected]

Thanks genius.

I sent it to your address.

So I am learning here a little because I have never used a Scaler and also not a ANY_TO_WORD

I have plugged some numbers in the SCALER but not getting anything on the output... will play some more and update soon

See below... and I also am not getting anything out, so I dont think your PLC is bad, I think its something in the logic