Digipot interface with VFD

Hi,

I am interfacing the AD5258 digipot IC with the VFD drive in order to give the analog voltage from 0 to 5V.



Since the entire PCB sharing the ground with the PCB,
--> The microcontroller experience some noises and unwanted behavior when the drive is ON ( Motor is Running)
--> The microcontroller works properly when the drive is OFF ( Motor is Stopped )

How can i avoid this noise pickup issue in processor..

Is there any digipot IC which can have optical isolation facility...

Hi,

a lot of informations missing:
* Is the micrcontroller supplied with the 5V_Out of the VFD? If not, how?
* Is VFD_GND connected with digipot_GND. If possible: do this.
* What about the GND connection to the microcontroller?
* How is the digipot supplied?
* Did you install all recommended power supply capacitors?

Use short, twisted and/or shielded cable between VFD and digipot. Use seperate wires for "B" and "GND".
Use short cable between microcontroller an digipot.

***
Noise pickup can be via air, or conductive via cabling.
Pickup is increased with high impedance signals.
Pickup is increased without proper GND wiring.
Influence of noise pickup can be reduced by proper filtering.
Thus a detailed assistance is not possible with your given information.

We don´t want to design a new circuit for you.... we just want to improve your circuit. Therefore you have to show us. Complete, with sufficient description.

Klaus

You should give as an idea of the involved µC/Digipot power and ground wiring as well as µC external connections.

I2C isolators are a possible option, common mode chokes might help, too.