Epson DFX-9000
Revision B
Operating Principles
Circuit operation
84
LF Motor drive circuit
The LF Motor is a HB stepping motor. A dedicated unipolar drive
control device for a 2-phase stepping motor uses paper sensor pulse
counts for position control. The speed is controlled using excited-cycle
and open-loop control. Figure 2-29 shows a circuit block diagram of the
LF motor.
Figure 2-29. LF Motor Drive Circuit Block Diagram
The input of an excited cycle output (M_TIM2) from the SoC ASIC to
the Mechanism Control ASIC provides automatic phase-switching
control. The phase data signal LFM [A:D] is output from the MOTOR
control section of the Mechanism Control ASIC, and the internal FET of
the LF motor driver turns ON when the output is “High-Z”, causing
current to be applied to the motor. The motor current passes through the
resistance detection section. At the same time, the voltage applied to the
detection section is compared with the voltage generated in the reference
voltage section of the LF motor driver internal circuit. If the applied
voltage exceeds the reference voltage, a logic operation AND is
performed between the LF motor driver internal comparing circuit and
the phase data signal to turn the internal FET OFF, keeping the output
current constant. The reference voltage generation section contains a
voltage divider with 4 resistances, and controls output current values for
acceleration, deceleration, constant speed, and stop.
ASIC
LFMA
LFMC
LFMB
LFMD
LFMI0
LFMI1
+42V
M_TIM2
Power Unit
Current detection
section
Reference
voltage
generation
section
LF Motor
Driver
Safety Check
detection section
LF MOTOR
Summary of Contents for DFX-9000
Page 1: ...EPSONDFX 9000 Serial Impact Dot Matrix Printer SEDM04003 SERVICE MANUAL ...
Page 8: ...C H A P T E R 1 PRODUCT DESCRIPTION ...
Page 61: ...Epson DFX 9000 Revision B Product Description Dimensions and weight 54 ...
Page 62: ...C H A P T E R 2 OPERATING PRINCIPLES ...
Page 99: ...Epson DFX 9000 Revision B Operating Principles Circuit operation 92 ...
Page 100: ...C H A P T E R 3 TROUBLESHOOTING ...
Page 104: ...Epson DFX 9000 Revision B Troubleshooting Overview 97 Mechanism initialization e e e e e ...
Page 107: ...Epson DFX 9000 Revision B Troubleshooting Overview 100 PAPER FEEDING FF APG APPROACH ...
Page 130: ...C H A P T E R 4 DISASSEMBLY AND ASSEMBLY ...
Page 218: ...C H A P T E R 5 ADJUSTMENT ...
Page 263: ...Epson DFX 9000 Revision B Adjustment Additional functions 256 ...
Page 264: ...C H A P T E R 6 MAINTENANCE ...
Page 286: ...C H A P T E R 7 APPENDIX ...
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Page 324: ...EPSON DFX 9000 Revision B Appendix Component Layout 317 7 4 Component Layout ...
Page 333: ...EPSON DFX 9000 Revision B Appendix Parts list 326 ...