Stepper Position Maintenance Mode (Spm) - Galil Motion Control DMC-21 5 Series User Manual

Command Summary - Stepper Motor Operation
Operand Summary - Stepper Motor Operation
OPERAND
_TDm
_TPm
_DEm
_DPm
_RPm
_ITm
_KSm
_MTm

Stepper Position Maintenance Mode (SPM)

The Galil controller can be set into the Stepper Position Maintenance (SPM) mode to handle the event of stepper
motor position error. The mode looks at position feedback from the main encoder and compares it to the
commanded step pulses. The position information is used to determine if there is any significant difference
between the commanded and the actual motor positions. If such error is detected, it is updated into a command
value for operator use. In addition, the SPM mode can be used as a method to correct for friction at the end of a
microstepping move. This capability provides closed-loop control at the application program level. SPM mode can
be used with Galil and non-Galil step drives.
SPM mode is configured, executed, and managed with seven commands. This mode also utilizes the
automatic subroutine allowing for automatic user-defined handling of an error event.
Command Summary - Stepper Motor Operation
A pulse is defined by the resolution of the step drive being used. Therefore, one pulse could be a full step, a half
step or a microstep.
Chapter 6 Programming Motion ▫ 69
COMMAND
DP Define Reference Position and Step Count Register
DE Define Encoder Position when using an encoder
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
Table 6.14: List of commands related to Stepper motor operation
Contains the value of the step count register for the 'm' axis
Contains the value of the main encoder for the 'm' axis
Contains the value of the step count register for the 'm' axis
Contains the value of the main encoder for the 'm' axis
Contains the commanded position generated by the profiler for the 'm' axis
Contains the value of the Independent Time constant for the 'm' axis
Contains the value of the Stepper Motor Smoothing Constant for the 'm' axis
Contains the motor type value for the 'm' axis
Table 6.15: List of operands related to Stepper motor operation
COMMAND
QS Error Magnitude in pulses
YA Step Drive Resolution in pulses/full motor step
YB Step Motor Resolution in full motor steps/revolution
YC Encoder resolution in counts/revolution
Error Correction in pulses
YR
YS Enable Stepper Position Maintenance Mode
OE Tell Position of Encoder
Table 6.16: List of operands related to Stepper Position Maintenance Mode
DESCRIPTION
DESCRIPTION
DESCRIPTION
#POSERR
DMC-21x5 User Manual 1.0a1