Hi Bob
Boy I like comprehensive answers!
Well when we go over next week I will switch controllers and keep my
fingers crossed and I will put in a new lithium cell as well.
Thanks;
Gran K6RIF
At 11:17 PM 12/8/2007, you wrote:
Hi Gran,
>I am sure this 5K does not have the V2.0 upgrade. There is one
other piece of information of interest. In the last two outages
other commercial equipment also had programming problems. I have
to wonder if the 5K is susceptible to low voltage. The dropping of
a single phase in the transmission line often will give a low
voltage like 80V instead of 120V. The Astron does not have a low
voltage cut out so I could see the output voltage dropping from
13.5 to say 6 to 8 volts under load. Could this cause a corruption
of memory in spite of the lithium battery?
It shouldn't happen. The 5K, 6K, and 7K have similar reset and
memory protection systems, which work like this: As the +5V supply
drops, the processor is forced into reset first, followed a short
time later by the RAM being disabled. The coin cell is switched in
to replace the +5V supply as the RAM's power source. The current
drawn from the cell is very low because the RAM is no longer being
written or read.
When power returns, the reverse occurs. As the voltage climbs, the
RAM's power supply is switched from the coin cell to the +5V supply
and the RAM is enabled. The processor's reset line is then released
and the processor begins executing its program.
If you try to run the controller under "brownout" conditions, +10V
regulator will lose regulation and output a voltage that is lower
than its input. If the +10V regulator can't supply the +5V regulator
with enough voltage, and the +5V output drops by >5%, the protection
system kicks in.
As extra protection, if the processor ever jumps the track and fails
to execute the program correctly, a watchdog circuit will notice
this and reset the processor. That restarts the program.
Since the 5K is quite old it's possible the RAM, the DS1232 (reset),
or the DS1210 (battery manager) is bad. I suppose it's even possible
that the INIT pushbutton is corroded closed so that every reset is a
cold start, but you'd know this by listening to the reset message
(an appended CW "C" = Cold Start). Or, the battery jumper is out,
or the cell was installed reversed, or ?..
73,
Bob
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