Loma IQ2 Service Manual page 34

CTB Constant:
This parameter is the number of pulses (ticks) per metre/foot of belt travel. To
calculate this figure for entry into the "*CTB constant" menu position, use either
the metric or imperial formula following:
Metric systems:
Where: d = the diameter of the roller to which the encoder is fitted in millimetres.
Imperial systems:
Where: d = the diameter of the roller to which the encoder is fitted in inches.
The maximum allowable CTB rate must not exceed 100 pulses per second. The
calculation to confirm this figure is as follows:
Maximum belt speed x CTB constant
The minimum allowable CTB rate to ensure accurate reject resolution must
exceed 4 pulses per coil gap. The coil gap distance for your detector (Rx) can
be found on the serial number plate located inside the control unit or from the
coil gap chart located earlier in this section.
The calculation to confirm the minimum number of pulses is as follows:
Metric systems:
Where: The coil Gap is in millimetres. The minimum belt speed is in metres.
Imperial systems:
Where:
minute.
Module 7026
CTB = Encoder pulses per revolution x 1000
CTB = Encoder pulses per revolution x 12
60
Coil Gap x [CTB constant x minimum belt speed] > = 4
Coil Gap x [CTB constant x minimum belt speed] > = 4
The coil Gap is in inches. The minimum belt speed is in feet per
Configuration and Set up Information
π d
π d
=
1000
12
< =100
5-12