can anyone explain how to control a servo motor??

[TheMaccabee]

Hello ,

Im really a beginner..can anyone explain me how to use a servo motor?
If you want o turn it to some degrees say by sending 1.8 ms on time pulse..Shall i send a pulse train till the time i want the shaft to remain in position.. or just send a pulse with that much ON time n stop???
Thanks

 

[dknguyen]

To get the servo to hold that position, you must continue to send pulses of that same width to "refresh" the servo position. If you stop sending pulses, the servo will stop holding that position and become "passive", if you send it too slow it will start to "droop".

For an RC servo motor, if you send a pulse that is 1.5ms long, it will go to the center position. If you send 1.8ms it will go a bit to the left (or was it right?), and if you send it 1.3ms, it will go a bit to the right (or was it left?). The width of the pulse tells the servo what position to move to. The frequency of the pulses doesn't matter too much as long as it's not too slow that it can't refresh the servo and not too fast that the servo cannot respond to it.

If you want a servo that will hold it's position without needing to refresh "until further notice" is something you have to custom build. You have to build a custom replacement PCB for the servo. You can use pulses or a serial protocal . Send a serial message or a pulse to indicate servo position and the servo just holds it until you send new position data. But it's something you have to build yourself.

 

[Sceadwian]

Most hoby servo's are spec'd for 90 degree of rotation. Center being a 1.5ms pulse and 1 or 2ms being +45 and -45 degrees from that center position. The pulse is typically sent 50 times per second, but if you're generating the signal yourself you can go as high as 75 times per second to increase responsivenses and applied torque at low deflections.

 

[gramo]

If you use a PIC, and a higher programming language such as PIC Basic (Proton+) it as easy as;

SERVO Pin , Rotation Value

Overview

Control a remote control type servo motor.

To control your servo

 

[TheMaccabee]

Thank You very much