Oce 3121 Technical & Service Manual page 716

The safety circuit used to isolate the motor M1 functions as follows:
If the microprocessor generates BMDWN=1, even though the bin home sensor
MS1 is actuated.
MS1 is actuated, with the bin at the lower limit position.
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If the upper sensor MS2 switches ON. (The sensor does not actuate under nor-
mal circumstances.)
BMUP=1, rotating the motor M1, and moving up the bin.
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The bin moves up too far, actuating MS2.
An error code will be logged.
If the stapler home sensor MS4 is OFF.
The stapler is not in the home position,
If the bin moved while the stapler was not in the home position, the stapler
could touch the paper.
To prevent this, the motor M1 is prevented from rotating in either direction
when the stapler home sensor is off.
The stapler is not in the home position (MS4 is
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OFF).
In addition, MS4 communicates to the microprocessor that MS4 is not in the
home position.
If the microprocessor generates BMDWN=1 or BMUP=1 at this time, Q42 and
Q44 switch off. The motor M1 will not rotate.
566 TSM Océ 3121
BHP=1
Q43 is switched ON.
BMDWN changes from '1' to '0', forcing M1 to stop
BUL=1.
Q41 is switched ON.
BMUP changes from '1' to '0', forcing M1 to stop.
SPLHP* is '1'.
Q42 and Q44 switch ON.
Functional description of the sorter