Can hardly believe what I am reading. I don’t get it – surprised to hear of
this firmware logic, for the first time.
Really? The response of (possibly any) model CPx
controller to an “interruption of power”, (for whatever cause), is
to kick its slew speed setting to the Maximum (or even HIGHER than maximum
user settable speed), and take off to who knows where ?
Indeed, this logic might explain its action on a current
CP4 problem, possibly caused by a CP4 “internal supply” power drop, in one
of its “DC converter’s voltage levels” due to a failing component – even
when the supplied power coming in, is perfectly solid.
Does the AMBER LED warning stand for motor Stall - as well as - Marginal
external/internal Power? If the latter is included and there is no actual motor
stall, then it might just continue racing away, with plenty of power to
spare for both motors, at the first loss of a DC shifted level.
Such runaway action ... doesn’t sound like a plan.. or
its not a sound plan.
Theoretically ... in similar scenario - a user might use
the keypad, or any app and start the mount tracking – worse, slewing via GOTO –
then unplug the keypad, or shutdown the PC, or indeed have a power brown-out in
the power supply, and the mount merrily takes a hike in a random direction,
possibly right into its pier.
Wouldn’t it be prudent to change the controller firmware
so it does a SAFE Park-In-Place, as though it were experiencing an actual
external power fail, either when power becomes “ropey”, or also when it loses
all communications with any source of command input(device, port, or software),
losing all channels to cease motion, guider input contact closures
Asimov’s first law of robotics (just as in
medicine) – if in doubt, do no harm.
There should be a “FAIL-SAFE” – a power “QUALITY” shutdown procedure in ALL
the controllers, and not just for a total power outage. A mount controller
“running away” in a crisis, almost sounds like robotic cowardice :-)
From: chris1011@... [ap-gto]
Sent: Saturday, August 5, 2017 7:22 PM
Subject: Re: [ap-gto] AP900 CP2 Issue
There is another possibility, the 12
volt power may not be making good connection on the CP2 power connector. The
connector has a small split pin, which acts as a spring. Take a small bladed
screwdriver and gently pry the tines apart on that center pin. This will insure
a proper contact with the 12 volts.
A 3rd possibility is a bad power
switch on your 12 volt supply. If that switch is making poor contact when you
turn it on, the CP2 can enter a runaway mode.