Re: AP900 CP2 Issue


Roland Christen
 


Can hardly believe what I am reading. I don’t get it – surprised to hear of this firmware logic, for the first time.
That problem was fixed in the CP3 and later editions. It was also fixed in the CP2 with the latest chip sets that we sent out many years ago.

Rolando


-----Original Message-----
From: 'Joseph Zeglinski' J.Zeglinski@... [ap-gto]
To: ap-gto
Sent: Sun, Aug 6, 2017 12:35 am
Subject: Re: [ap-gto] AP900 CP2 Issue



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.
Scary, indeed.
 
    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 included?
 
    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  :-)
 
Joe
 
 
From: chris1011@... [ap-gto]
Sent: Saturday, August 5, 2017 7:22 PM
To: ap-gto@...
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.

Rolando
 


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