Teknic CLEARPATH MCVC Series User Manual page 94

C P M C / S D U
L E A R A T H
S PWM D
ETTING A
T , I .
EKNIC NC
M R . 3 . 0 9
S E R A N U A L E V
EADBAND
The deadband expands the range about the 50% PWM mark that is
interpreted as the "zero torque setting" by ClearPath. This gives the user a
reliable way to ensure that motor torque is completely turned off when the
PWM duty cycle is set at (or "close enough" to) 50%.
Max. Torque
(CCW Rotation)
Torque = 0
Max. Torque
(CW Rotation)
0
10
+/- 5% PWM deadband setting
In bi-polar mode, turning off torque is achieved, in theory, by applying a
50% duty cycle PWM signal to Input B. However, it can be difficult to set a
perfect 50% duty cycle. In fact, a very small amount of torque may still be
produced by the motor, even when duty cycle is apparently set to 50%. A
deadband helps guarantee torque is fully off when you expect it to be.
Example: If the user sets a +/-5% deadband, any PWM signal with a
duty cycle between 45% and 55% (i.e., in the deadband) is interpreted as a
zero-torque command by ClearPath.
Note: As deadband setting increases, the slope of torque vs. duty cycle
increases as illustrated below.
Deadband
(+/- 5%)
20 30 40 50 60
Duty Cycle
Why use a deadband?
9 4
100
70 80 90
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