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Getting a (RC) servo to move...

Posted by HugoW 
Getting a (RC) servo to move...
November 26, 2017 09:26AM
Hi,

I have replaced my RAMPS set-up with an MKS SBase V1.3 board and I am almost done setting it up. The only thing I cannot get working is the servo I have which rotates the Z-probe down before homing and up again after. I added this to the config, between the lines anouncing the switch modules and the block for the PWM control of a fan:

# Switch module for servo control
switch.servo.enable                            true             # Enable this module
switch.servo.input_on_command                  M280             # M280 S7.5 would be midway
switch.servo.input_off_command                 M281             # Same as M280 S0 0% duty cycle, effectively off
switch.servo.output_pin                        1.23             # Must be a PWM capable pin
switch.servo.output_type                       hwpwm            # H/W pwm output settable with S parameter in the input_on_comand
#switch.servo.pwm_period_ms                    20               # set period to 20ms (50Hz) default is 50Hz

I checked pin 1.23 is a PWM-able pin. If I tell the set-up "M280 S5", it should turn fully one way. "M280 S10" fully the other way, and "M280 S7.5" would / should be dead in the middle. But the servo connected does not move. I checked it gets 5V power, I checked the servo works in an RC car and I switched between servos. But to no avail. Any idea what I do wrong? The only thing I can think of is that the PWM signal of the board is 3.3V, not 5V. But I feel a modern servo shouldn't really mind?

Thanks,

Hugo
Re: Getting a (RC) servo to move...
November 27, 2017 08:28AM
Sorry buddy, but I think you and me both goofed by buying from MKS. We won't find help here.
Re: Getting a (RC) servo to move...
November 27, 2017 10:55PM
Huh, why? Is it me or is Trump involved? Bummer. Any idea where I can get info?

Cheers,

Hugo
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