Galil Motion Control DMC-42 0 Series, User Manual

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First, the controller generates a motion profile in accordance with the motion commands.
Second, the profiler generates pulses as prescribed by the motion profile. The pulses that are generated by the
motion profiler can be monitored by the command, RP (Reference Position). RP gives the absolute value of the
position as determined by the motion profiler. The command, DP, can be used to set the value of the reference
position. For example, DP 0, defines the reference position of the X axis to be zero.
Third, the output of the motion profiler is filtered by the stepper smoothing filter. This filter adds a delay in the
output of the stepper motor pulses. The amount of delay depends on the parameter which is specified by the
command, KS. As mentioned earlier, there will always be some amount of stepper motor smoothing.
Fourth, the output of the stepper smoothing filter is buffered and is available for input to the stepper motor driver.
The pulses which are generated by the smoothing filter can be monitored by the command, TD (Tell Dual). TD gives
the absolute value of the position as determined by actual output of the buffer. The command, DP sets the value
of the step count register as well as the value of the reference position. For example, DP 0, defines the reference
position of the X axis to be zero.
Motion Profiler
Stepper Smoothing Filter
(Adds a Delay)
Output Buffer
Step Count Register (TD) Reference Position (RP)
Output
(To Stepper Driver)
Motion Complete Trippoint
When used in stepper mode, the MC command will hold up execution of the proceeding commands until the
controller has generated the same number of steps out of the step count register as specified in the commanded
position. The MC trippoint (Motion Complete) is generally more useful than AM trippoint (After Motion) since the
step pulses can be delayed from the commanded position due to stepper motor smoothing.
Using an Encoder with Stepper Motors
An encoder may be used on a stepper motor to check the actual motor position with the commanded position. If
an encoder is used, it must be connected to the main encoder input. Note: The auxiliary encoder is not available
while operating with stepper motors. The position of the encoder can be interrogated by using the command, TP.
The position value can be defined by using the command, DE.
Note: Closed loop operation with a stepper motor is not possible.
Command Summary - Stepper Motor Operation
COMMAND DESCRIPTION
DE Define Encoder Position (When using an encoder)
DP Define Reference Position and Step Count Register
IT Motion Profile Smoothing - Independent Time Constant
KS Stepper Motor Smoothing
MT Motor Type (2,-2,2.5 or -2.5 for stepper motors)
RP
Report Commanded Position
TD Report number of step pulses generated by controller
TP Tell Position of Encoder
Chapter 6 Programming Motion ▫ 91 DMC-42x0 User Manual