OPERATING PRINCIPLES
‰PI Control :
PI control keeps the CR motor speed constant using the encoder pulses ENCA and ENCB with the gate array E05B36. The E05B36 generates the PWM (pulse width modulation) signal according to the CR motor speed to the PWM port of the gate array and determines the duty of the carriage drive timing.CR ports I0, I1, and I2 output the drive signal for the CR motor.
‰Acceleration control :
Until the carriage speed reaches the constant speed set by PI control, acceleration control determines the speed of the carriage. The printer can print while the carriage is accelerating. The carriage speed moves to constant control speed smoothly to prevent the CR motor from exceeding the constant control speed. The E05B36 gate array controls the motor driver
Speed 0 - SP1
1.It causes the carriage to accelerate.
2.Because the control circuit measures time periods with the encoder signal, when the carriage speed reaches SP1, it changes to the next sequence (SP1 - SP2).
SP1 - SP2
1.When the carriage speed reaches SP1, the printer uses the acceleration driving mode, based on the duty data, and the rest of the time, it uses Deceleration driving mode 2.
2.During this time the control circuit measures time periods using the encoder signal, and controls the following:
∙When duty data becomes Dutymin before the carriage speed reaches SP2. Then, when the carriage speed reaches SP2, the next sequence
∙When the carriage speed reaches SP2 before duty data becomes Dutymin, the next sequence
SP2 -
When the carriage speed reaches SP2, PI control oversees the carriage speed.
Curve | SPref |
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SP2 |
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Acceleration | SP1 |
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| 0 |
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Signal | Acceleration | Constant |
| Speed | |
Control |
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Deceleration 2 | Control | |
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Figure 2-21. CR Motor Drive Circuit Block Diagram
Rev. B |
