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Mechanics and Construction => Mechanics and Construction => Topic started by: mahm on November 09, 2013, 04:13:13 PM

Title: Hitec HS 422 servo query
Post by: mahm on November 09, 2013, 04:13:13 PM
hey guys, i need to use this servo HS 422 for 180 degree of rotation ,is there any precision issues for going above 45 degree for both sides?  thank you  :)
https://www.sparkfun.com/products/11884 (https://www.sparkfun.com/products/11884)
Title: Re: Hitec HS 422 servo query
Post by: olivthill on November 10, 2013, 08:58:41 AM
It can rotate up to 180 degrees.

What are the minimum and maximum frequencies of the PWM you feed it with?

In the link you gave is written: "Direction: Clockwise/ Pulse Traveling 1500-1900usec".
That's not correct. It should be 900-2100µs.
Title: Re: Hitec HS 422 servo query
Post by: mahm on November 10, 2013, 02:22:23 PM
thanks for replying, that's exactly what confuses me and it's actually from the motor datasheet.
http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/hs422-31422S.pdf (http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/hs422-31422S.pdf)
that's why i'm asking for info from someone who did use that model
are you sure about the 180 degree? and what is pulse width range in us? thanks again
Title: Re: Hitec HS 422 servo query
Post by: jwatte on November 10, 2013, 05:51:34 PM
"us" means microseconds.

The specification of 1500-1900 microseconds for clockwise rotation means that from 1500 us (center) it will rotate clockwise as it goes to 1900 microseconds, and it will be approximately 45 degrees clockwise rotated at 1900 microseconds. This means it should be at 90 degrees clockwise at 2300 microseconds, and 90 degrees counterclockwise at 700 microseconds.

The measurement of the pulse width is the microseconds measurement. 1500 microseconds is 1.5 milliseconds. A 50 Hz control rate sends a pulse every 20 milliseconds (every 20000 microseconds.)

Title: Re: Hitec HS 422 servo query
Post by: mahm on November 12, 2013, 10:31:17 AM
"us" means microseconds.

The specification of 1500-1900 microseconds for clockwise rotation means that from 1500 us (center) it will rotate clockwise as it goes to 1900 microseconds, and it will be approximately 45 degrees clockwise rotated at 1900 microseconds. This means it should be at 90 degrees clockwise at 2300 microseconds, and 90 degrees counterclockwise at 700 microseconds.

The measurement of the pulse width is the microseconds measurement. 1500 microseconds is 1.5 milliseconds. A 50 Hz control rate sends a pulse every 20 milliseconds (every 20000 microseconds.)

so it does rotate up to 180 degree , thanks a lot for your help :)