"Jumpy" Analog Inputs- Input 53 Speed Reference Filtering

Hi There- my new favorite customer Ryan was looking at a VFD this morning that had a “jumpy” analog input from the building control system.

We see this occasionally where the 0-10v signal from the EMCS is moving around constantly by fractions of a volt, it doesn’t hurt anything— A VFD isn’t like a damper actuator where hunting will wear it out— But in this case the customer didnt like that the display was constantly changing between “running on reference” and “ramping” like it didn’t make the setpoint.

Who knows where these tiny voltage changes come from, but you can smooth them out by adding filtering to the VFD input— See below. Change the default filtering in parameter 6-16 from .001s to around 1s or so and it will smooth out those little bumps. If you set the filtering too high it will slow down the VFD response to actual reference changes.