Using An Encoder With Stepper Motors; Command Summary - Stepper Motor Operation - Galil Motion Control DMC-1600 Series User Manual

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
Reference Position (RP)
*Note: Although steps can be missed by over lapping moves, when the last stepper motion has
been completed the stepper will be in the correct position.
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
DE
DP
IT
KS
102 • Chapter 6 Programming Motion
Stepper Smoothing Filter
(Adds a Delay)
DESCRIPTION
Define Encoder Position (When using an encoder)
Define Reference Position and Step Count Register
Motion Profile Smoothing - Independent Time Constant
Stepper Motor Smoothing
Output Buffer
Step Count Register (TD)
Output
(To Stepper Driver)
DMC-1600