Re: AP1200 PE/PEMPro Query

Roland Christen

In a message dated 10/19/2007 9:12:41 AM Central Daylight Time,
richard.kinsey@... writes:

Hi Ray, one question please. Having checked all the settings in
PEMPro and the ASCOM settings, I discovered that the "PEM Playback"
check-box in the ASCOM settings was checked. Would this setting
override the PEC enable/disable options in PEMPro and the PEC
settings within the AP hand-controller?
The way the servo works is that it will do whatever it is commanded from
whatever source. If the keypad is set to PEM off, this is a one time command that
is given at startup. This command is not sent over and over during the
operation of the mount. No command is sent more than once from the keypad or from any
other source. Therefore, if a command from any source is sent to turn PEM ON,
then that is the command that is acted on in the servo - i.e. it is always
the last command sent to the servo that is acted on. This is true of all
commands sent to the servo. If no commands are sent, then all is quiet on the
communication lines.

This is contrary to how other mount systems (like the Meade LX200) work. In
the Meade system they use a distributed computing concept that continuously
sends software traffic at megabit rates back and forth between central mother
board, motor controllers and keypad, so that all these components always talk to
each other, and all must be in perfect synchrony in order for the system to
work. This has both strengths and weaknesses. In our system, only the servo
components inside the CP1,2,3 box continuously talk to each other, and all outside
peripherals are treated as independent entities. Therefore all peripherals,
including the keypad are silent unless you, the user, activates them. And then
the communication is always only one way - toward the servo. The servo does
not initiate communication with any outside peripheral. It does not send any
info to any peripheral ON ITS OWN for any reason. It will send info out to a
peripheral if asked for the info by that peripheral.


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