MPIAxisEstopModify

Definition

	typedef struct MPIAxisEstopModify { double deceleration; double decelerationJerk; double jerkPercent; } MPIAxisEstopModify
	Change History: Modified in 04.00. Added in 03.03.00

Description

MPIAxisEstopModify is used with mpiAxisConfigGet(...) and mpiAxisConfigSet(...) as part of the MPIAxisConfig structure. This structure can be used to configure the deceleration and jerk applied to a motor when an EStopModify event occurs.

Any of the limits can be configured to generate an EStopModify instead of a standard EStop (a standard EStop stops the motor by stepping down the feedrate until it reaches 0.0).

Below are Motion Scope plots of DAC and actual velocity during deceleration. Stopping a motion with either MPIActionSTOP or MPIActionE_STOP may cause DAC spikes when axis count is high and acceleration feedforward is used. This causes an audible noise in the system. Using MPIActionE_STOP_MODIFY will eliminate this problem.

MPIActionSTOP causes DAC spikes for high axis count and when acceleration feedforward is used.

MPIActionE_STOP_MODIFY eliminates DAC spikes and audible system noise.

For more information, see mpiMotorEventConfigSet(...) and mpiMotorEventConfigGet(...).

NOTE: Standard firmware uses jerkPercent and does not support decelerationJerk. See the MPITrajectory structure documentation.

deceleration	Specifies the Deceleration applied to the motor when an EStopModify occurs. Units are counts/sec².
decelerationJerk	Specifies the Jerk applied to the motor when an EstopModify occurs. Units are counts/sec³. Jerk moves specified in counts/sec³ are not supported in the standard firmware. Please contact MEI if this feature is required in your application.
jerkPercent	Specifies the JerkPercent applied to the motor when an EstopModify occurs. Units are in percent. Range is 0.0 to 100.0.

Sample Code

MPIAxisConfig axisConfig;

mpiAxisConfigGet()

/* Set other parameters */

…

/* You will want to use decelerationJerk for custom Jerk firmware. */
axisConfig.estopModify.deceleration = 10000; axisConfig.estopModify.jerkPercent = 66;

mpiAxisConfigSet()