Galil DMC-13X8 ユーザーズマニュアル

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Chapter 6  Programming Motion  
  92  
USER MANUAL 
are moving back and forth.  For example, when operating with servo motors, the trippoint AM (After 
Motion) is used to determine when the motion profiler is complete and is prepared to execute a new 
motion command.  However when operating in stepper mode, the controller may still be generating 
step pulses when the motion profiler is complete.  This is caused by the stepper motor smoothing filter, 
KS.  To understand this, consider the steps the controller executes to generate step pulses: 
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.  The default value for KS is 2 which corresponds to a time constant of 6 sample 
periods. 
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.