Galil Motion Control DMC-18 2 Series User Manual page 183

PWM/STEP OUT
PWM/STEP OUT
Sign/Direction
Error
Output 1-Output 8
Inputs
Encoder, A+, B+
Encoder Index, I+
Encoder, A-, B-, I-
Abort
Reset
Forward Limit Switch
Reverse Limit Switch
172 ● Appendices
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PWM/STEP OUT is used for directly driving power bridges for DC
servo motors or for driving step motor amplifiers. For servo motors: If
you are using a conventional amplifier that accepts a +/-10 Volt analog
signal, this pin is not used and should be left open. The switching
frequency is 16.7 Khz. The PWM output is available in two formats:
Inverter and Sign Magnitude. In the Inverter mode, the PWM signal is
.2% duty cycle for full negative voltage, 50% for 0 Voltage and 99.8%
for full positive voltage. In the Sign Magnitude Mode (Jumper SM),
the PWM signal is 0% for 0 Voltage, 99.6% for full voltage and the
sign of the Motor Command is available at the sign output.
For stepmotors: The STEP OUT pin produces a series of pulses for
input to a step motor driver. The pulses may either be low or high.
The pulse width is 50%. Upon Reset, the output will be low if the SM
jumper is on. If the SM jumper is not on, the output will be Tristate.
Used with PWM signal to give the sign of the motor command for
servo amplifiers or direction for step motors.
The signal goes low when the position error on any axis exceeds the
value specified by the error limit command, ER.
These 8 TTL outputs are uncommitted and may be designated by the
user to toggle relays and trigger external events. The output lines are
toggled by Set Bit, SB, and Clear Bit, CB, instructions. The OP
instruction is used to define the state of all the bits of the Output port.
Position feedback from incremental encoder with two channels in
quadrature, CHA and CHB. The encoder may be analog or TTL. Any
resolution encoder may be used as long as the maximum frequency
does not exceed 12,000,000 quadrature states/sec. The controller
performs quadrature decoding of the encoder signals resulting in a
resolution of quadrature counts (4 x encoder cycles). Note: Encoders
that produce outputs in the format of pulses and direction may also be
used by inputting the pulses into CHA and direction into Channel B
and using the CE command to configure this mode.
Once-Per-Revolution encoder pulse. Used in Homing sequence or Find
Index command to define home on an encoder index.
Differential inputs from encoder. May be input along with CHA, CHB
for noise immunity of encoder signals. The CHA- and CHB- inputs are
optional.
A low input stops commanded motion instantly without a controlled
deceleration. Also aborts motion program.
A low input resets the state of the processor to its power-on condition.
The previously saved state of the controller, along with parameter
values, and saved sequences are restored.
When active, inhibits motion in forward direction. Also causes
execution of limit switch subroutine, #LIMSWI. The polarity of the
limit switch may be set with the CN command.
When active, inhibits motion in reverse direction. Also causes
execution of limit switch subroutine, #LIMSWI. The polarity of the
limit switch may be set with the CN command.
DMC-18x2