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Kicker On----When low, turns on the Kicker motor.
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Kicker Clk----This is a pulse-width modulated signal that controls the stepping rate of the Kicker
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Motor.
Processor Heater Control----Controls the duty cycle of the Processor Heater.
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Translate Clk----This is a pulse-width modulated signal that controls the stepping rate of the Optics
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Translation Stepper Motor.
Processor Clk----This is a pulse-width modulated signal that controls the stepping rate of the
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Processor Stepper Motor.
6-4-2-2.
Film Processor Control
The MCS Master CPU and Address Decoder FPGA control the temperature of the Processor heater as
follows. A 1,000 ohm RTD is used to sense heater temperature. The RTD output is converted to a
frequency modulated signal on the MCS board. This signal, PROC TEMP FREQUENCY IN, is sent to the
CPU, where the proper duty cycle for the application of 120 vac heater power is determined. The CPU
sends a PROC HEATER CONTROL signal to the Address Decoder FPGA, which generates the PROC
SSR DRIVE signal. This pulse-width modulated signal (low-going active) energizes the solid state relay on
the Processor Interface Board that routes ac power to the heater.
6-4-2-3.
Stepper Motor Drive
Two types of drive circuits are used on the MCS to operate the four stepper motors that are directly
controlled by the MCS Board:
Film Centering Stepper and Platen Roller Stepper----Drivers for these motors require an enable signal
and two phase signals (square waves) spaced 90 degrees apart. The phase signals determine the
direction of current through the motors and the direction of rotation as shown in Table 6-1.
Stepper Motor Driver
Platen Roller Stepper Motor
Film Centering Stepper Motor
To start a motor, the CPU configures the phasing channels for the appropriate direction and sends the
required enabling signal, PLATEN ON or CENTERING ON (active low). To stop the motor, the enabling
signal is driven high. It is not necessary to stop the phasing signals to stop the motor. The Film Centering
Stepper Motor is driven at 12 volts dc. The Platen Roller Stepper uses 24 volts dc because it requires
high rotational speed and needs higher power to overcome motor winding inductance.
Optics Translation Stepper, Processor Stepper, Vertical Transport Stepper, and Kicker
Stepper----The drivers for these 4 motors have microcontrollers that include micro-stepping data tables.
The optics translation stepper micro receives input control signals for on/off, direction, and fast or slow
speed, as well as clock pulses (TRANSLATE CLK). The other 3 stepper micros have only an on/off control
signal, in addition to its clock input , since these 3 motors have only a single direction and speed. Each
clock pulse from the CPU to a micro results in one micro step. The micros have different code sets for
controlling motor speed:
In the optics translation code set, there are 16 microsteps per one major step at scanning speed
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(slow). This corresponds to 3200 microsteps per revolution on a 200 step per revolution motor.
Running at high speed, there are approximately 12 microsteps per major step.
2005 July Rev. B
7F3318
Table 6-1. Stepper Motor Phase/Direction Relationship
Leading Phase
Phase 1
Phase 2
Phase 1
Phase 2
Section 6 - - Theory of Operation
Motor Direction
Load Direction
Unload Direction
Home Direction
Centering Direction
6-15
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Troubleshooting
