HSR-8498-HB 25 August 08 David Buckley SERVO commands angle is from 10 to 190 equivalent to 180deg range 100 is the default mid point Comparison ---------- RoboBasic count Servo #18 right ankle roll +ve lateral up 52 - 116 = 64 => -48 +16 about 100 uS Servo #18 right ankle roll +ve lateral up 1210 - 1830 = 620 uS => -290 +330 about 1500 uS Servo #20 right knee +ve straight 23 - 190 = 167 (190 is servo limit) Servo #20 right knee +ve straight 550 - 2430 = 1880 uS (endstop to endstop) There has been some mention on the RoboSavvey Forum that because the HSR-8498-HB servos are digital they only need one pulse to go to a position. My tests indicate that this is not the case. On test the servo was run from a Parallax BS2 which allowed complete control of the pulse length, frame rate and number of pulses. When run on intermittent pulses these servos, unlike analog servos, can get confused and lock-up against an end stop. Only the right ankle servo was tested. 'RN right ankle ' forward =2190uS ' vertical =1080uS ' back = 520uS 'if any pulse is <440uS then the servo switches off and has to be power cycled to respond to pulses again. 'if >=460uS and the pulse length rapidly changes to 460uS then servo switches off until >~570uS. 'if the number of pulses sent is less than ~30 then sometimes the servo starts up and goes beyond ' its set point and locks-up hard against an end stop. Analog servos operate fine with infrequent and/or erratic frame times as long as they are >~10mS, all that happens is that the torque drops off as the frame time increases beyond ~20mS. The HSR-8498-HB can not be safely operated like that.