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Trolley Positioning
In addition to speed regulation, the motor encoder
also performs trolley positioning. As stated
previously, one motor rotation corresponds to a
7.8125cm (3.08in) movement along the rail. Motor
rotation is also equal to 128 rotations per 10
meters of movement.
At maximum motor speed, the encoder sends a
TOP_SYNC signal once every 7.3ms and the 16-
bit internal counter increments every 7.3ms.
However, if the duration between two pulses is less
than 6ms, it is considered a false reading and is
not used.
Using the above specifications as a reference
point, trolley position is determined by counting
motor rotations (using the TOP_SYNC signal from
the encoder) and by comparing current and
previous counter values.
Counter increment or decrement is performed
according to trolley movement (forward or
backward). Trolley direction is known by the
software and confirmed by a SENS signal.
Two optical sensors (A and B) detect the pass-by
from one rail section to another and also recognize
the start and end of the rail. The start of the rail is
detected only by sensor A and the end of the rail is
detected by both sensors (A and B). Sensor B also
detects a spot label positioned at the end of each
track section.
The ability to differentiate the start and end of the
rail in conjunction with the new positioning system
enables the trolley to move even when the optical
strips are reached and thus reduce the length of
the dead zone.
A built-in odometer records trolley movement in
kilometers. This measurement is performed by
incrementing a counter at the TOP_SYNC pulse
independent of direction. When the value reaches
640000, the odometer increments by 1.
SENSORRAIL IIIE
SERVICE GUIDE
I Max Circuit
To avoid burning up the motor due to electrical
over current, an "I Max" circuit is installed on the
CPU. This circuitry provides feedback of 0.6V per
ampere (with an extreme limitation of 5.2A). If over-
current is detected, the trolley sends a disable
command (PC3-Port C) to the PWM drivers to stop
the trolley motor.
On-board Adjustments
The CPU board does not have any adjustments.
Port Assignments
Port assignments related to trolley functions are as
follows:
Port A:
Not used
PBO to PB6: (not used)
Port B:
PB7: PWM (motor speed control)
Port C:
PC0: Default LED 2 (lit when a default occurs;
motor is disabled)
PC1: CMD (determines the CW or CCW rotation of
the motor)
PC2: default LED 1 (lit when a default occurs;
motor is disabled)
PC3: DISABLE (motor ON or OFF)
PC4: not used
PC5: BRAKE (Motor brake ON or OFF)
PC6 and PC7: not used
Port D:
PD0: B channel from the encoder
PD1: A channel from the encoder
PD2: RX from Dome (through RS232/RS422
converter)
PD3: TX to Dome (through RS232/RS422
converter)
PD4: TOP_SYNC from the encoder
PD5: not used
PD6: A channel from the encoder
PD7: not used
Port E:
PE0: RX from the matrix
PE1: TX to the matrix
PE2: not used
PE3: Watchdog (voltage critical value 20V +/- 13%)
PE4: not used
PE5: Optical sensor A
PE6: not used
PE7: Optical sensor B
Port F:
PF0: Temperature sensor (not used)
PF1: Not used
PF2: I Max measurement
PF3: Not used
PF4: JTAG TCK (for firmware update purposes)
PF5: JTAG TMS (for firmware update purposes)
PF6: JTAG TDO (for firmware update purposes)
PF7: JTAG TDI (for firmware update purposes)
Port G:
Not used
5 of 34
8200-0593-03, REV. A
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