Minolta Di251, Service Manual

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FrameMaker Ver5.5E(PC)Di251/Di351 MECHANICAL/ELECTRICAL
05.03.01
M-6
5. CPU OVERRUN MONITOR FUNCTION
• The CPU overrun monitor function (watchdog function) is a self-monitoring function that
determines whether any of the CPUs mounted on the copier overruns.
• If this function detects that a CPU overruns, the copier automatically resets the CPU,
restarting the logic circuit and mechanism.
• The copier CPU not only performs the self-monitoring function, but also checks the com-
munication status with the option’s CPU.
5-1. Processing Performed during Watchdog Function
The following operations are performed when a CPU operates erratically.
If a copier CPU overruns:
• All CPUs including those of the options are reset and a restart sequence is performed.
• If the overrun occurs during a copy cycle, the copier tries to feed all sheets of paper out of
itself before resetting the CPU. (Any sheet of paper that could not be fed out of the copier
is detected as a sheet of paper left when the restart sequence is later carried out.)
If an erratic operation is detected in communications with the option’s CPU:
• The copier turns OFF and ON the option’s relay and performs a restart sequence of the
option.
• If the overrun occurs during a copy cycle, the copier stops the paper take-up operation,
feeds all sheets of paper out of itself, and then performs a restart sequence of the option.