Moons' MSSTAC6 User Manual page 29

MSSTAC6 Step Motor Drive User Manual
Pulse Input Mode is for systems where the position of the motor is determined by a digital input signal
in the form of pulses.
The three modes available are:
Pulse & Direction. A signal such as that generated by a step motor controller is used. In this mode,
the frequency of the pulses fed into one input determines the speed of the motor. Direction of rotation is
determined by a signal fed into another input. Either an ON or OFF signal can be configured to represent
clockwise motion.
CW & CCW Pulse. The drive has two inputs allocated to this feature and the motor will move CW or
CCW depending on which input the pulse is fed into.
A & B Quadrature. Signals fed to the drive from a master encoder control the movement of the motor.
The encoder may be mounted on a shaft on the machine or can be another motor in the system.
For all the Pulse Input modes you will need to determine a value to enter into the Electronic Gearing Box,
an explanation on how to do this is given in the next section.
Steps/Rev
Steps/Rev allows adjustment of the way the drive responds to incoming step pulses. If a step motor
drive in an existing application is being replaced with a new drive, the new drive can be configured here to
have the same number of steps/rev as the old one.
In a new application, this value should be entered in accordance with the pulse source or indexer. The
motor will provide smoother, more precise motion with a higher step count, but when the frequency of the
indexer is limited, the steps/rev may need to be reduced to achieve the desired speed range. For example,
in an application requiring a maximum speed of 20 revs/second where the indexer is limited to a 100kHz
maximum pulse rate, the steps/rev should be no higher than 5000.
A particular value may also be entered to make one step result in a convenient increment of motion. For
example, in a linear motion application using a lead screw with a pitch of 5 turns per inch, 20,000 steps/rev
will provide a nominal movement of .00001 inches per step. Move lengths can be more easily calculated with
this method. For a metric application with the same lead screw, 50800 steps/rev would result in .0001 mm
per step.
Encoder following applications can also be easily configured with a particular Steps/Rev value. To drive
the motor two turns for every one turn of a 2000 count/rev (500 line) encoder, the value of 1000 steps/rev
would be entered.
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