Old 11-30-2005, 06:53 PM
  #13  
mglavin
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Default RE: Do I need a servo programmer for digital servos

A digital servo, any digital servo is better than its analog counterpart. It’s simply the nature of the digital amplifier that makes all the difference, better precision and more power again will be realized as compared to an analog counterpart. That said digital servos are comprised of the same components as there analog cousins less the amplifier in play. Cored motors verses coreless motors are another determining factor for realizing increased precision, speed and repeatable results all else being equal.

The qualities of the components servos are comprised in Hitec’s circumstance are as good as there OEM counterparts in nearly all cases. All this stuff is out sourced there are only so many variables available to manufacture these components, either the components meet or exceed the OEM requirement or not. The specifications of the individual amplifiers are the only significant OEM variable IMO. Hitec digitals all use the essentially the same digital amp tuned to motor specific variables of each servo. Engineers plastic, assembly techniques and technology are all basically the same gear-train alloys and plastic formulations are proprietary. Electric motors and potentiometers are sourced too, in fact ALL Hitec Digitals use the same high quality feedback potentiometer as JR uses in there high end digitals. JR’s refitted top cap and re-powered 8611A uses the same motor and vendor Hitec specified from the gate for the 5955/5995TG servos.

Hitec digitals are shipped with the deadband parameter set to "2" of 9 possible settings. With a Hitec Hand-Held Programmer one can lower the deadband to 1 of 9. This will increase the servos ability to offer better repeatable results.

The 3-poled cored motor of the 5600 series digitals is not as precise as a coreless motored digital servo. A coreless motor can infinitely stop and hold the position commanded of it, whereas a cored motor will always rest or stop between the poles, therefore precision is a factor of same. That said a Hitec 645MG high power sport servo with a the atypical metal gear-train tolerances and cored motor maybe more powerful than other standard servos its still a standard servo on steroids with like precision and deadband. Moving up to a Digital 5645 will garner increased precision and power but its still a cored motor unit with metal-gear tolerances…

PPM does off some degree of precision not afforded 1024 PCM systems. It’s a numbers game. There are 1200 steps plausible with our TX’s, our radios typically have a MAXIMUM pulse width swing of 600 micro-seconds either side of center. 1024 PCM modulation utilizes 1024 steps while PPM utilizes 1200 steps total swing. Additionally as mentioned previously EPA, travel volumes or end-point percentages drastically affect the steps available for control responses. LOWER percentages numbers with MAX throw setups throw out hundreds of finite control step positions, thus causing coarser or notchy control response. Another variable is the trim button response of the TX in play, some are programmable parameters (i.e., high end TX’s) while others are fixed values, what this means is trim value for each step might be 5 micro-second as compared to a more precision setup with 1 micro-second response.
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