Hi,
I'm working on my first project using the following "induction motor" & "speed controller"
What I'm looking for is replacing the knob in the speed controller with a keypad for a higher rpm accuracy, is it possible?
If it is, please recommend any source to go through it.

Thanks in advance,

 

It's possible, but depends on exact way potentiometer is used.
A multiplying D/A converter could be the active part.
The keypad interface can go Many ways.
A simpler answer is a 10 turn potentiometer for better control.
For precise setpoints, use switching between values of resistors.

 

Hi,
I'm working on my first project using the following "induction motor" & "speed controller"
What I'm looking for is replacing the knob in the speed controller with a keypad for a higher rpm accuracy, is it possible?
If it is, please recommend any source to go through it.

Thanks in advance,

Accuracy will probably require some form of servo loop. Between your keypad and the current driver - there's a few opportunities for ending up with a non linear transfer curve. That doesn't take account of loading either.

Most manufacturers are eliminating analogue controls wherever they can. There were various EEPROM based controls used in 80s/90s TVs that are fairly simple to use. Uptake of consumer appliance serial bus was pretty rapid - you'll need something like a PIC or AVR to feed it data.

You should detect the RPM and display it. You can go open loop if you want to - but it isn't that much of a leap to proper servo control.

 

I couldn't get the manual in English, but if it has Modbus/RS425 interface as many VFD's do now, you just enter the rpm value required serially rather than the analogue signal.
But without an encoder option feedback the closest rpm control is if the drive has phase/vector control.
Max.