Micro Serial 8 Servo Ctrl:Incremental position change?


using the Controller and the .Net test program (colinkarpfinger.com/pololu/), i noticed a strange
a) i turn on power on the controller: orange led lights up
b) i set a value (regardles if i operate thge controller in pololu or SSC mode), then push “Send”:

  1. the orange led turns dark
  2. green flashes
  3. red flashes
  4. the servo moves “a bit” to the desired position
  5. orange led lights up

c) repeating step b), the servo moves (in steps) until reaching the desired position

Does anybody have an idea what the reason for this behaviour could be?

kind regards,


How are you powering your servos and your servo controller?

Once you send a command, the orange LED should go off and stay off. The the red LED lighting briefly indicates that something bad is happening, and then the orange LED coming back on indicates that the controller has been reset. It sounds to me like your power source can’t supply enough current, and when the motor starts to move the voltage from your power source drops low enough to reset the controller.


Thanks for your reply- it seems your analysis was correct.
I attached an extra power source for the controller and the behaviour is now different:

  • orange light after powerup
  • sending a command (regardless of mini-scc/pololu mode) results in:
  • briefly flashing green led
  • servo moves to one limit, motor does not stop

Any further ideas?

Kind regards and thanks for any assistance,

Can you describe your power system, and the command bytes you’re sending to the servo controller (plus what you’re sending them from and how it is connected to the controller)? I’m particularly confused that you say you see the same results in both Pololu and Mini-SSC II mode. Are you sending two different mode-specific commands, or the same command in each mode?


Hi Adam,

thanks for your patience & support.

  • the controller ist hooked up to a pc native (aka no usb converter) serial port
  • servo power is a ~5v battery pack
  • controller power is a ~6v battery pack
  • regarding pololu/mini-scc mode: what i meant was that i tried both modes (so “different mode-specific commands” with jumper correctly set/open)
  • I used the program i mentioned in my first post for testing - but using my own program, i get the same results (so it looks as if it’s hardware related?)
  • in my own program, i used mini-ssc mode with 0xff,0x07,0x80 (for example)

Kind regards, Chris

Actually, if anything it sounds like there might be something wrong with your servo, like a problem with the potentiometer. Are you seeing this behavior with multiple servos or just one?