Position control using stepper and pot

[Rohith_elec]

Dear sky_123,
i need the help only for motion controlling the stepper and obtaining the feedback,
so that i can control the instrument using labview

 

[sky_123]

Right.. in that case, I suggest a feedback pot is also used, and then your motor (or stepper motor) is not operating 'blind'. Basically, use the motor to
control both the feedback pot and the intended pot.

 

[Rohith_elec]

cant i use the single pot to do both tasks, if both are at 5V ?

 

[sky_123]

Sure, but that involves you opening up your instrument. And it is an assumption that the pot inside the instrument has 5V control. If it does, and you are opening up your instrument, then why not just directly supply a 0..5V signal to remotely control the instrument and remove the instrument's pot.

 

[Rohith_elec]

yes sky_123,
i will try that too ,
I already opened the instrument ...

 

[zia]

dear rohit do u require project with simulation in proteus if yes yhen i will be happy to help u.

 

[milind.a.kulkarni]

Hi to All,

Here will be some of my comments -

1) Rohit, first of all let draw the the Block diagram of the work that you want to do- Bcz you need PC -> Communication interface ( I think mostly UART ) -> PIC micro-controller board-> Command translation logic -> Stepper motor driver logic -> Stepper motor connected to POT....
2) After this let note down the details of the specification and requirement of the system like -Power rating available, No of revolution, position control in degrees, Response time , Rating of stepper motor, Surge handing capabilities ( Like suppression like dv/dt etc.) , fail-safe method requirements
3) Then one can decide the fixing of clock frequency of micro-controller followed with module of implementation like Command translation logic , Stepper motor driver logic etc.
4) Then let decide the method of fail-safe method

Then one can think of how to implement it....

At least as a system level every body will be clear....

Note-

Rohit - you said 120 A constant current source, this is very high current rating and dealing with this current rating ( maintaining it for constant current ) will have some voltage surge effect ......Generally these kind of requirements are handled using PWM control of FETS where multiple FET's are operated in parallel.....

So before even think of stepper motor I will suggest you look for all of such alternative....

Good Luck