Epson FX 1170 Service Manual - Page 70
Llqfp-1, IC2C1
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REV.-A 2.3.4 Carriage Motor Drive Circuit The carriage motor drive circuit controls the CR motor. An open loop, constant current drive arrangement runs the CR motor. 2-2 and 1-2 phases are used to excite the motor. A 2-2 phase step is equivalent to a 1-2 phase step doubled. Table 2-5 describes the motor drive modes. The CR motor drive circuit of the SLA7024M (IC6) detects and regulates the amount of current flowing in the carriage motor coil. The current flowing through the coil varies depending on the speed of the CR motor. The CPU sets the amount of current via the l/O port of the gate array. Signals are sent to the ports (L, M, HOLD) on the SLA7024M. The SLA7024M sets the coil current depending on the CR motor speed. The printer may stop printing to protect the CR motor from overheating if a continuous printing of short columns (less than 10 columns) is repeated. The printer uses CPU ports P60 to P63 exclusively to control the CR motor. CPU (IC2C1) P60 INA P61 INB P62 IN-A P63 IN-B E05A66YA (IC4) GPC4 Data PC5 Bus PC6 LOW MIDDLE HOLD MOTOR 1 rAS--S--E--M--B-LY. , -C-.R-----, CRA I I 1 8 [ 8 CR-A i 1 II lqfp-1 1 I t 1 t 1, I 1 CRB , I I 1 1 1 I IL CR-B 8 L1 1 1 A CRCOM Gp l-l 1 GiD 4-ph, 200-P HB type pulse motor 35VDC +8Y0 -7~o 5.4Sh10Y0 (per phase) (at 25 'C) Figure 2-27. Carriage Motor Drive Circuit Table 2-6. Carriage Motor Drive Modes Speed mode PPS Excitation phase Characters printed 4/3 9/8 1 5/6 2/3 1/2 5/1 2 1/4 5/24 1/8 4468 2-2 3840 2-2 3357 2-2 2800 2-2 2240 2-2 1680 1-2 1400 1-2 840 1-2 700 1-2 420 1-2 Superdraft Superdraft copy Draft 10 cpi 4/3 High duty NLQ 5/12 High duty 1/4 High duty 2-27