Epson DFX-8500 Service Manual page 84

Deceleration control:
Deceleration control provides smooth deceleration and prevents rapid vibration.
The duty data for deceleration control is determined for each printing mode. Pulse width modulation (PWM)
determines each printing mode.
Current speed - SP3
1. The printer uses Deceleration driving mode 2, based on the duty data, and the rest of the time, it uses
Deceleration driving mode 1.
2. During deceleration driving mode 1, the control circuit measures time periods using the encoder signal,
and controls the following:


When duty data reaches Duty
Speed 0) begins.


When the carriage speed reaches SP3 before duty data reaches Duty
Speed 0) begins.
SP3 - Speed 0
1. When the carriage speed reaches SP3, Deceleration driving mode 3 begins. This control method is the
inverse-continuity break method.
2. During deceleration driving mode 3, the control circuit measures time periods using the encoder signal.
When the rising edge of next pulse is not detected after 1.5 seconds, Deceleration driving mode 1 begins
and the control circuit controls short-break.
SPref
SP3
0
Deceleration 2
or
Deceleration 1
before the carriage speed reaches SP3, the next sequence (SP3 -
min1
1 2
PWM Perodic Time
Figure 2-22. Carriage Motor Drive Circuit Block Diagram
OPERATING PRINCIPLES
, the next sequence (SP3 -
min1
3
Deceleration 3
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