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Need Explaination On Altivar61 Freq Terminology

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#1 gado


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Posted 21 July 2008 - 04:34 AM


I am re-posting this query because maybe you guys doesnt understand my query due to typographical error.

We are using a Telemecanique Altivar61 on our pumps with the 4-20mA input to the VSD comes from a DCS system. I am a bit confused why our pumps here with same ratings is geting different frequency displays. Is it due to improper parameter set-up?

If anyone who is familiar with this drive, can you please explain what is the difference and functions of the following:
1. Reference Frequency
2. Output frequency
3. Measured Frequency


#2 Shozza


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Posted 22 July 2008 - 05:37 AM

Hi Gado,

I haven't had a lot of experience with the Altivar61 but here's what I found.

1. Reference Frequency
This is the parameter where you would set the desired operating frequency or set point if using a PID setup. It's probably being set via the 4-20mA input.

2. Output Frequency
This refers to the frequency being output by the drive to the motor so is basically a readout of the frequency that the motor is currently operating at.

3. Measured Frequency
This parameter refers to the motor frequency when an encoder is being used to measure the actual motor speed. If no encoder is being used it will probably display 0.

Hopefully it helps!


#3 dip04051978


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Posted 22 July 2008 - 07:28 AM

Pl.share the value of each above parameter & at what ref. i.e value of current input 4-20mA.

Pl.share the value of each above parameter & at what ref. i.e value of current input 4-20mA.

#4 marke


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Posted 22 July 2008 - 08:56 AM

Hello gado

The reference frequency is the target operating frequency of the drive. i.e. the speed that you want to run at. This is often referred to as the set point frequency.

The output frequency is the frequency of the output current which will equal the target frequency except when the drive is OFF, accelerating or decelerating, or voltage or current limiting.

I would expect the measured frequency to be equal to the output frequency.

Best regards,

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