Printronix L5535, Руководство по обслуживанию

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II–192
Appendix A
Explanation Of Circuits According To Function
The TPOS signal validates (that is, gates) the drive pulses of both the current
switchover signal (PMDRV) and the various motor phases, along with turning
on the power supply relay (RY2).
The current switchover circuit switches over the comparator voltage of the
current detection voltage V
B
by this PMDRV signal, between the motor drive
and detent states, as follows:
During the motor drive state: 0.99 V
During the detent state: 0.53 V
As a result, the current flowing to the motor becomes nearly constant, with
only slight ripples of 1.5 A/phase and 0.8 A/phase. The relationship between
the comparator output voltage V
A
and the current detection voltage V
B
is as
shown in the following graph:
The motor is a 2-phase excitation type, and its drive pulses are as shown in
the following charts:
During positive rotation
1 2 3 4
TPFA10 1 1 0 0
TPFB10 0 1 1 0
TPFA11 0 0 1 1
TPFB11 1 0 0 1
During negative rotation
1 2 3 4
TPFA10 0 0 1 1
TPFB10 0 1 1 0
TPFA11 1 1 0 0
TPFB11 1 0 0 1
The reference position of the transfer elevator motor occurs when the transfer
unit is in its highest position. When the mechanism control firmware initializes
the printer, the firmware rotates the elevator motor until it detects that the
upper limit sensor is off (corresponding to the transfer unit in its highest
Comparator Voltage
V
B
0
V
A
24V
0