IFM VTV 122 Vibration Transmitter

General
1

Hello, is there anyone who use this type of sensor? I still a bit confuse about this sensor output and communication protocol.

This is the technical specification from ifm website: VTV122 - Vibration transmitter - ifm

My question:

  1. In the website its said that the sensor output is analog (4-20mA) so to get the measurement value i need to convert it to the Velocity RMS (mm/s)?
  2. I cant find any communication protocol information from the technical specification.
  3. I want to visualize the data with time domain graph and frequency domain spectrum. Can I convert the Velocity RMS (mm/s) data from the sensor with FFT to create the frequency domain spectrum?
2

Welcome to the forum @union

You will need to use a 4-20ma interface to get the values. If you google for usb 4-20ma input' it will suggest many possible devices.

There isn't any communication, it is just an analogue value. 4ma represents the minimum reading, 20ma represents the max.

Looking at the spec it seems to me that it gives you the RMS velocity, but I don't see how you can frequence from that. However, I don't know about vibration monitors so I may be wrong. What do you think that the device will tell you?

3

Ahhh I see, so I need to use some converter device for this sensor right? Just say I want to use modbus RTU RS485 for this sensor communication with node-red. So I need to find a device that convert the 4-20mA analogue signal interface to RS485 right?

Yes this sensor gives the RMS velocity (V RMS) value. To get the frequency value I need to convert the time domain graph (X- bar = time, Y-bar = V RMS) to frequency domain graph with Fast Fourier Transform. (X-bar = frequency, Y-bar = Amplitude).
[I'm not sure if the **Amplitude** can be a V RMS or must be just velocity, this is what I'm asking for, because some example just using the velocity value not the V RMS for the raw data]

4

Why do that? Why not use a direct 4-20ma to USB converter?

5

I can't find 4-20ma to usb converter in my country, so Im planning to use 4-20mA to rs485 and then rs 485 to usb converter

6

I really don't think that device is going to give you data that will allow frequency domain determination. I am not an expert in that area though.

7

Hi, we company has a product which can sample 4~20mA and deal it in NodeRED natively.

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An application note

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8

hmm ok, thank you for the help

9

Sorry, but I just can use product that sold in my country and I can't find this product in my country marketplace.

10

Hi, there are third-party agents such as CSSBuy, who can help oversea customers to buy our produts from China.
Any thing further you'd like to know, please feel free to contact with me.

11

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