Hi Guys,

Here is a little information on a project I am working now. I have a sensor that outputs a pulse depending on the amount of fluid running through it. The higher the flow rate, the higher the pulse it puts out. I hooked up an oscilloscope on the sensor and it is a standard high low voltage (square wave)with a frequency of about 20 Hz. The problem is that a VFD (variable frequency drive) must be running when the system is running and this generates a ton of noise. The sensor is actually going in to a DAQ so I can get data into Labview and instead of Labview reading the 20 Hz signal, it reads a frequency of 1k - 1 Mhz because of the noise coming from the VFD. With the VFD not running, Labview reads the 20 Hz signal just fine.

Should I just try to figure out this issue on the software side or can I implement some filter to get my 20Hz signal out?

Thanks in advance!

 

Hello,

You could try to make a low pass filter.
You should look what frequencies are of importance.
Is the powersupplypoint near the sensor decoupled?
You could try to feed the sensor through a choke with a capacitor accross the powersupplypoints of the sensor.

Greetings,
Bertus