Specifications
REV.-A
2.3.4 MOTOR, CR Drive Circuit
Figure 2-22 shows the MOTOR, CR
driie
circuit. An open-loop, constant-current drive control is used
to drive the MOTOR, CR. The motor is driven by 2-2 phase excitation and 1-2 phase excitation. 2-2
phase excitation corresponds to two 1-2 phase excitation steps. Thus, for each single step phase
change of a 2-2 phase excitation motor, the carriage moves 1/120 inch. For each single step phase
change of a 1-2 phase excitation motor, the carriage moves 1/240 inch.
The MOTOR, CR
driie
circuit of the STK-67128 detects the amount of current flow in the MOTOR, CR
coil and regulates it. The current flowing through the coil varies depending on the speed of the
MOTOR, CR.
The amount of current is set by the CPU via the
E05A50
l/O port. Signals are sent to Vrefl or
Vref2
on the STK-67128. The STK-67128 sets the coil current to mnespond to the MOTOR, CR speed.
Ports P60 to P63 on the CPU are used exclusively as phase control
potts
for the stepping motor.
-.
----
--
.
.
(IC21)
P60
P61
Al
P62
BI
P63
-
IAI
/B1
E05A50
STK-6712
MOTOR,CR
%l=s-=~~:;
/Ad
-1=3
I
IB4
:
Current
k
VREFA
Control
Circuit
VREFB
.--..--.---.-
Figure 2-22. MOTOR, CR Drive Circuit
Tshla
7-I%
MOTOR. CR
Driva
Mnchs
)
1
2-17
.
----
-
-.
...
-
.
-.
.,
-.
.
-----
-------
Drive Mode
Extension Type
Type Drive Frequency Standard Print Character
3 x speed
2-2 phase
2695
PPS
Draft
2 x speed
2-2 phase
1773
pps
High Speed LQ
1.5 x speed
2-2 phase
1347
pps
Draft(Emphasis,
Condensed)
4/3 x speed
1-2 phase
1191
pps
1 x speed
1-2 phase
1796
P@
LQ
3/4 x speed
1-2 phase
1347
pps
2/3 x speed
1-2 phase
1190
pps
1/2 x speed
1-2 phase
898 PPS