Hello, i didn't knew where to post this so i came to the general electronics section. The things is,
i have a MG995R Servo motor that i'll be using to make a custom ATC(Automatic Tool Changer)
for my CNC milling machine.

I am running the program that controls the position of the servo with a PIC18F4550, i am checking the
wave it's being formed on the output pin of my uC and it's pretty nice, very well controlled, bah bah.

So this is not a problem. The real problem is, it doesn't matter which pulse width i try to go with, my
servo will always move CW and reach it's limit and stay there, it doesn't matter if i change the pulse width
or anything.

I need to make a 180° movement, please help.

As a side note, i was using a SG90, that blue one with plastic parts, and it was working nicely.

This is the servo.

 

Seems a little light of a device to operate a CNC machine-tool changer!
Max.

 

You need to give details of the output waveform from your controller and also that data on the servo. (In case it is different from the normal model control servo standard.) Post pictures of the output waveform from your oscilloscope. I agree with Max that it will not be powerful enough for a tool changer.

Les.

 

The MG995R is a digital servo, so internally it is generating drive pulses at ~300Hz and the average current draw is higher than for an analogue servo. Perhaps those factors result in blips on the power supply and hence erratic behaviour. Try adding extra decoupling capacitors to the supply. Like the others, I have doubts about that servo being useful for tool-changing (unless the tools are micro ones for watch-making ).

 

I was about to upload, 3 videos, 3 images, but i discovered the problem. It turns out my LM7805 was limiting the current reaching the servo, so he didn't had the muscles to go back to it's old position or even control it's position, when i connected directly to a 5v, 10A source it worked nicely, just for the record, these are the waveforms.




Now it's changing position like a charm.

One thing i was surprised is the LM7805, in my mind i thought, if it is current problem then the LM7805 should
get fryed and not limit the current, but instead it was limitting the current for the servo.

 

Show us a picture of the tool changer.
Max.

 

After December 2, i will be able to post anything. It's for a large competition on my country, can't risk it.

 

[QUOTE="A

One thing i was surprised is the LM7805, in my mind i thought, if it is current problem then the LM7805 should
get fryed and not limit the current, but instead it was limitting the current for the servo.[/QUOTE]

The LM7805 should shut down in over current and over temp conditions, and it should reset automatically when those conditions are removed.

 

Is this a new servo? If not, maybe it been modified for continuous rotation.