AMC1200-Q1: Measuring 0 V to 600 VRMS, measuring frequency 0 Hz - 70 Hz Isolation Stage.

Mike_3007

Expert 2055 points

Part Number: AMC1200-Q1
Other Parts Discussed in Thread: AMC1200, AMC1311, PMP9480

Hi everyone.

This is Mike and I want to thank you all for your support , and here is the next situation:

I want to measure the output of a three phase generator that has Wye conection. Just I'll take two phases and that is for monitoring the voltage and the frequency of that signal. I've searched about techniques to measure high voltages and I found the AMC´s family of OpAmps. I think is a little easier when one has to measure a large signal with a constant voltage and frequency (here, at México, 127Vrms , 60 Hz) but in this application, the signal varies and just I want to make sure that the design will work. I can´t measure yet because my material has doesn´t arrived, I think it will be here in ¡ 3 Weeks !

The datasheet says the max Vin is 250mVpp so I design a voltage divider that at 600V and here is the result

When the input is at 50 Vrms, I'll have at the output 18 mV, the question is if at that level the AMC1200-Q1 Does still work so fine at the output?

over 6 years ago

0 Tom Hendrick over 6 years ago

TI__Guru**** 168435 points

Hola Mike!

Welcome to our e2e Forum! This sounds like an interesting project! The AMC1200-Q1 can work with small signals, so there should not be any issue with your 18mV input.

0 Mike_3007 over 6 years ago in reply to Tom Hendrick

Expert 2055 points

Hola Tom ! xD

The end application is for a control of a green-energy generator. In fact I found, at least, four ways to do it. I don't know if I have to get a new question to talk about them.

0 Tom Hendrick over 6 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Hi Mike -

If you have more questions about the AMC1200, feel free to ask! As long as follow up questions pertain to the same general topic, there is no need to start a new discussion.

0 Mike_3007 over 6 years ago in reply to Tom Hendrick

Expert 2055 points

Hi, Sorry for answering too late. My components has not arrived yet, so I can not confirm the AMC1200-Q1 works properly, I'm concerned about the input signal, I mean, it is a noisy signal, better said, it is rich in harmonics, and it think that degrades the signal and my measurement will be compromise. What do you think?

0 Tom Hendrick over 6 years ago in reply to Mike_3007

TI__Guru**** 168435 points

No worries Mike - you get your equipment back soon correct? Let us know what you see when you get things running.

0 Tom Hendrick over 6 years ago in reply to Tom Hendrick

TI__Guru**** 168435 points

Hi Mike!

Have you gotten your gear back yet? How are your tests going?

0 Mike_3007 over 6 years ago in reply to Tom Hendrick

Expert 2055 points

Hi Tom Hendrick
Finally my components are arrived, Just give me a week to tell you the result, I'm excited because of that. I' ve been looking at the forum, asking about other things regards mcu C2000, but that´s another story. This development I think wil be good

0 Tom Hendrick over 6 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Great! Looking forward to your feedback!

0 Tom Hendrick over 5 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Hi Mike!

How is this project going?

0 Mike_3007 over 5 years ago in reply to Tom Hendrick

Expert 2055 points

Hi Tom.

As the first post where there is my circuit with resistors. Using the AMC1200-Q1, Do you think that circuit its ok to the input (+) and the input (-) ?

I have another question. I saw an app note about this IC. In case of my resistor arrangement doesn't work I'm thinking to use this diagram. But just the part of voltage's measure

As I told you the signal is coming from a Three Phase Wye motor connection So I have to consider the RMS is the Vpp/ sqrt(3). Do you think it will work?

The maximum voltage i have to measure is 600 VRMS

Or if you can give some design guidelines with AMC1200-Q1 about the calculus of this, in order to improve my circuit

Thank you some much

Best Regards

Mike

0 Tom Hendrick over 5 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Hi Mike,

Have you tried the original circuit yet? Just curious, but what is the document number you found this new circuit in? Using 1K as the shunt is getting a little 'large' for the AMC1200. If all you want to do is measure the voltage, you might also consider taking a look at the AMC1311, which has a high impedance input and can accommodate voltage up to 2V.

0 Mike_3007 over 5 years ago in reply to Tom Hendrick

Expert 2055 points

Hi Tom
I've not tried because I had to make some code in the microcontroller ( in fact, I've been so active at the C2000 Forum) , and other chores that I have here in my job. So I already finish the firmware I need to test it. The diagram I found it at tidrbx8.pdf, it is the design reference of "PMP9480: Isolated Bias Supplies + Isolated Amplifier Combo for Line Voltage or Current Measurement"
I will look for the OpAmp you said
I think I had ordered it with the other components, just to probe various op amps.

0 Mike_3007 over 5 years ago in reply to Mike_3007

Expert 2055 points

Tom?

0 Tom Hendrick over 5 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Hi Mike - what can I do for you?

0 Mike_3007 over 5 years ago in reply to Tom Hendrick

Expert 2055 points

Hi Tom, just waiting to answer if it is ok the design I saw on the pdf.
Thanks a lot
Regards
Mike

0 Tom Hendrick over 5 years ago in reply to Mike_3007

TI__Guru**** 168435 points

Hi Mike,

I was not involved in that TI Design, but I believe the authors published their measurement results. The basic concepts are fine, no issues there, it's just with the 1K load/shunt they used, you are going to have a little more gain/offset error to contend with. All fine - so long as you account for the errors in your calibration routine.

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AMC1200-Q1: Measuring 0 V to 600 VRMS, measuring frequency 0 Hz - 70 Hz Isolation Stage.