Author Topic: current measuring  (Read 2410 times)

0 Members and 1 Guest are viewing this topic.

Offline izuaTopic starter

  • Supreme Robot
  • *****
  • Posts: 682
  • Helpful? 0
    • izua electronics
current measuring
« on: May 31, 2008, 06:33:11 PM »
I have a stepper motor. I'm driving it with microstep. The supply voltage is a known value (but may change). I'm going for 40 volts (for now) - but it's a requirment for this to work in a given voltage range.

Each winding is driven by an Hbridge, commanded in PWM (20khz, 800 steps). What I want to do is measure the current going into each winding, or overall, into the motor. I could use a sense resistor, or a current monitor, but since I'm driving this on PWM and not DC, I might need some way to smooth it out. An analog filter with an opamp (if using a sense resistor) perhaps?

Any ideas or schematics?
Thanks!
Logged
Check out my homepage for in depth tutorials on microcontrollers and electronics.

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,704
  • Helpful? 173
    • Society of Robots
Re: current measuring
« Reply #1 on: June 07, 2008, 04:41:03 PM »
It depends on what type of measurement you want.

If you want an average measurement, just use a resistor and capacitor circuit to smooth out the reading.

If you want 'instant' readings, don't use anything. For example, on a project I'm working on I need ~40 power measurements per second. My microcontroller makes the reading through ADC, then spits out the data by USB to my PC.
Logged
 

SMF spam blocked by CleanTalk