phytron
31
MA 2107-A005 EN
8.3
pulse
Control
Input
Maximum step frequency: 500 kHz
Minimum pulse width: 1 µs
A negative control pulse of 1 µs causes a motor step. The step is done with the falling
flank of the control pulse and the current is changed from run to stop current. If the time
between two control pulses is more than 40 ms, the stop current is activated.
The control pulse sequence must not suddenly start or stop, if the control pulse frequency
is higher than the start/stop frequency*
)
of the motor. Mispositioning of the drive would be
the result.
*
)
The start/stop frequency is defined as that frequency, from which a stepper motor can start from
standstill without losing a step. Typical values for the start/stop frequency are 200 to 2000 Hz. The
exact value depends on the load torque and the load inertia of the motor shaft.
If the motor is to be operated above the start/stop frequency range, the indexer has to
generate frequency ramps to accelerate and decelerate the motor.
8.4 Motor Direction Input
This signal sets the direction of the motor.
If the input optocoupler is
not
energized, the motor rotates in the preferential direction. If
the input optocoupler is powered, the selected motor direction is reversed.
The signal must only be modified when the motor is at a standstill or turns with the
frequency within the start/stop frequency.
Changing the motor direction when the motor is running will cause step losses and/or stop
the motor.
Important:
The signal must be constantly active 1
μ
s after the falling flank of the control
pulse (see fig.13).
Fig. 14: Control pulse of MSX
The preferential motor direction is set by the MOTOR DIRECTION DIP switch (behind the
front panel) relating to the logic level.