Datalogic Laser Sentinel, Instruction Manual, Page: 98 / 152

FUNCTIONS
80
SAFERY LASER SCANNER
• If the vehicle speed is in the range between -30 cm/s and -10 cm/s or +10 cm/s
and +30 cm/s, the Encoder
Δ can be exceeded for max. 60 s.
• If the vehicle speed is in the range ≤ -30 cm/s or ≥ +30 cm/s, the Encoder Δ can be
exceeded for max. 20 s.
• If the vehicle speed is in the range ≤ -10 cm/s or ≥ +10 cm/s, then different direc-
tions of rotation on the encoder are only tolerated for max. 0.4 s.
NOTE
Encoder 1 / 2 [p/cm]
Encoder (1 and 2) pulse number per centimeter. For both encoders the minimum value
is 50 (default), and the maximum value is 1,000.
This is based on the number of pulses the encoder supplies per revolution, and on the
ratio between the vehicle wheel and the friction wheel on which the encoder is
mounted.
To calculate this value, follow the example below:
• The vehicle wheel has a diameter of 40 cm.
• The friction wheel on which the encoder is mounted has a diameter of 4 cm.
• The incremental encoder supplies 1000 pulses per revolution.
The circumference of the vehicle wheel is 40 cm x π = 125.66 cm.
One revolution of the vehicle wheel corresponds to 10 revolutions of the friction wheel,
and therefore the encoder supplies 10,000 pulses per revolution of the vehicle wheel.
To calculate the Encoder Ratio (EncR), i.e. number of pulses per centimeter of distance
covered by the vehicle, use the following formula:
EncR = P
rev
/ C
Where:
P
rev
= pulses per revolution of the vehicle wheel
C = circumference of the vehicle wheel
When the speed measured by the two encoders is not the same, the higher
speed value is used as a reference for this calculation.