hi
Siemens does not sell power meters covering that range.
PAC3220 can only do typical range 40-60hz

The voltage is coming from the transformer which is stepped down by the voltage transfomer to 400V.
Transformer is fed by the VFD with the sine filter so the measured voltage is sine rather than PWM signal.

Any ideas highly welcomed.
Regards

 

There are several devices for that. They integrate the voltage and calculate the true RMS voltage (equivalent DC like voltage of the AC signal that gives the same effect).

For example, a true RMS Fluke 179 multimeter can measure voltage, True RMS up to 1000Vac with a frequency range of 45Hz-1kHz.
See: https://www.conrad.nl/nl/p/fluke-17...rgave-counts-6000-120556.html#productTechData

You can also try to use a true RMS voltage to 4-20mA signal convertor. This one from Phoenix measures true RMS from 0-400Vac 45-1000Hz. https://electromen.com/en/products/item/galvanic-isolators/u-v-mv/EM-M25

But I'm sure there are other brands.

 

There are several devices for that. They integrate the voltage and calculate the true RMS voltage (equivalent DC like voltage of the AC signal that gives the same effect).

For example, a true RMS Fluke 179 multimeter can measure voltage, True RMS up to 1000Vac with a frequency range of 45Hz-1kHz.
See: https://www.conrad.nl/nl/p/fluke-17...rgave-counts-6000-120556.html#productTechData

You can also try to use a true RMS voltage to 4-20mA signal convertor. This one from Phoenix measures true RMS from 0-400Vac 45-1000Hz. https://electromen.com/en/products/item/galvanic-isolators/u-v-mv/EM-M25

But I'm sure there are other brands.

Massive thanks for reply however the lower range of 10hz is used most of the time. Any device that would cover 10-200hz. So far i have found none and looked for some time today. If you dont know - what brands/companies would you contact first?

 

You said you use a VFD.
Most VFDs have a ModBUS RTU RS-485 connection.
With that you can read out all the current, voltage and power signals: problem solved.

 

You said you use a VFD.
Most VFDs have a ModBUS RTU RS-485 connection.
With that you can read out all the current, voltage and power signals: problem solved.

That is great idea to read from the VFD however after VFD there is a sine filter which as we know causes some non linear losses of the voltage (below 10V). Customer requirements is to have the final reading from the transformer output (2000V is stepped down to 400V for the reading) to be sure what voltage exactly is at the transformer output which feeds something else.
Any idea how to solve?

 

I would contact ABB, they are specialized in transformers and transformer monitoring systems.

 

I would contact ABB, they are specialized in transformers and transformer monitoring systems.

thanks a lot for giving me direction
i am on the phone to them right now

 

I understand you have an AC voltage you want to measure. What do you want to know about it?

• Max/min
• RMS
• True RMS
• Frequency
• Waveform capture
• FFT details
• Other

How often do you want to take a measurement?

Are you looking to manually take a measurement and write it down, or want something automated?

Where to you want the measured data to go?

 

I understand you have an AC voltage you want to measure. What do you want to know about it?

• Max/min
• RMS
• True RMS
• Frequency
• Waveform capture
• FFT details
• Other

How often do you want to take a measurement?

Are you looking to manually take a measurement and write it down, or want something automated?

Where to you want the measured data to go?

hi i need line to line voltage and currents in each phase plus power factor plus total active power. Data to be sent over modbus tcp to the plc

 

I don't know of a COTS device to do that. Please let us know what you find.

Our products can measure the signals (with some sort of transducers), and speak Modbus TCP, but at this time don't do all the math you need, so you would need some sort of host computer to do all the math. For example, you could have a raspberry pi connected to a LabJack via USB. You could write a program for the pi that reads the waveforms from the LabJack, does the math to calculate your desired parameters, and writes those values back to the LabJack so the PLC can read them from the LabJack via Modbus TCP. Definitely not a simple COTS solution, but if nothing else is more suited it can be done.

 

I understand you have an AC voltage you want to measure. What do you want to know about it?

• Max/min
• RMS
• True RMS
• Frequency
• Waveform capture
• FFT details
• Other

How often do you want to take a measurement?

Are you looking to manually take a measurement and write it down, or want something automated?

Where to you want the measured data to go?

i need to measure true RMS voltage (400V max line to line), current in each phase, power factor and total active power
the challenge seems to be the wide range of the frequencies in which the measurment is taken, the measurement can be taken every 1s or 2s or more often if possible

 

I don't know of a COTS device to do that. Please let us know what you find.

Our products can measure the signals (with some sort of transducers), and speak Modbus TCP, but at this time don't do all the math you need, so you would need some sort of host computer to do all the math. For example, you could have a raspberry pi connected to a LabJack via USB. You could write a program for the pi that reads the waveforms from the LabJack, does the math to calculate your desired parameters, and writes those values back to the LabJack so the PLC can read them from the LabJack via Modbus TCP. Definitely not a simple COTS solution, but if nothing else is more suited it can be done.

massive thanks for reply - can you explain bit more more what labjack does - is it hardware, software or both?

 

massive thanks for reply - can you explain bit more more what labjack does - is it hardware, software or both?
also why does the measurement of the power meter is such a challenge in the wide frequency range?
suprised that there is no off the shelf solution for that already

 

We are primarily a hardware company. Our specialty is computer-based data acquisition & control devices. If you can't find something off the shelf that does what you need out of the box, and this task must be done, one of our devices along with some custom software would allow you to accomplish this requirement, but certainly not a trivial task.

 

I use an RPM1656, when the waveshape fault is triggered, it captures data points at every milli seconds to construct the new waveshape. The reference volt and frequency must be setup at the onset. A 500ns spike will trigger the waveshape fault and start high resolution recording. The newly plotted graph can then be measured for freq.