Motor rotation occurs by sequentially changing the phase and current signals to the two motor
coils. Motor speed is controlled by how rapidly the signals are changed. Following is a state
table where each state change rotates the document motor rotor 1/400 of a revolution (1/120"
of document motion) and there are 8 distinct states before the pattern repeats. Direction of
motor rotation can be reversed by moving up rather than down through the state table. The 2
motor windings are labeled Phase A and Phase B and the phase and 2 current level signals for
each winding are shown. The state table for the carriage motor is similar but the states with 0%
current are skipped so each state change rotates the carriage motor rotor 1/200 of a revolution
(1/120" of carriage motion).
Phase A I0A I1A Phase B I0B I1B A Current B Current
1 0 0 1 0 0 100% Forward 100% Forward <--
1 0 0 0 1 1 100% Forward 0% Reverse |
1 0 0 0 0 0 100% Forward 100% Reverse |
0 1 1 0 0 0 0% Reverse 100% Reverse |
0 0 0 0 0 0 100% Reverse 100% Reverse |
0 0 0 1 1 1 100% Reverse 0% Forward |
0 0 0 1 0 0 100% Reverse 100% Forward |
1 1 1 1 0 0 0% Forward 100% Forward ---
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