I have a question regarding stardard servo range and pwm, looking at hitech manufactures data say for a 645 servo, it gives a resultion of the following.
1500 - mid point
400 - ±45Deg
that says to me that i would get the following movement
1900 - +45Deg
1500 - centered
1100 - -45 deg
800 - full 90deg range
However reading this forums and other infomation it seems that its not 45 deg each direction but 90 so therefore assuming lineararity
2300 - +90Deg
1500 - centered
700 - -45 deg
1600 - full 180deg range
Now linxmotion “what is a servo” says
Normal
2100 - +45
1500 - Centered
900 - 145
1200 - full 90deg range
Extended
750 - +90
1500 - Centered
2250 - -90
1500 - full 180deg range
Now the crunch part every one seems to say 1-2ms = 0-180deg so
2000 - +90
1500 - centered
1000 - -90
1000 - 180 Full Range
So i`m wondering which infomation to use, as the pulse width length difference between full open and fully closed is kinda fundemental to pc based rc control
standard range for r/c use is 1000ms to 2000ms corresponding to +/- 45 degrees and just about every hobby servo will do that.
reality is that pulse durations outside that range will result in a larger angle range, however the limits vary not only between manufacturers but in many cases between servo models. there is also no formal linearity specification outside the recommended operating range, and even the 1500ms = 0 can have an offset of a few degrees.
so if you were trying to use hobby servos for some sort of precision application it may be in your best interest to make certain you can calibrate 0 degree offset from 1500 as well as end points that relate a pulse duration to angle displacement in both directions.
the applications such as the SEQ that Lynxmotion sells have a calibration screen where you can do this as well as set soft limits.
