About Enable Mode

Axis Enable Mode

The enable mode for an axis, specified via the SetEnableMode function, controls the value of the position command that is first issued to the drive as it is enabling.

The two modes, which select between SETPOINT and CURRENT VALUE, are described below:

Value	Mode	Description
0	MESURE	The feedback position of an axis is read from the drive, and the drive is commanded to servo to that position while it is enabling. This prevents the axis from moving when it is enabling. This is the default enabling mode and is also the highly recommended mode for enabling.
1	SETPOINT	The last commanded position while disabling the axis is used as the position command to the drive while enabling. This mode allows the axis to continue servoing to the same position when the axis is continually enabled and deactivated. If the axis moves while disabled, it will snap back to the prior setpoint as soon as the axis is enabled. The profile of the snap movement is controlled only by the servo gain parameters in the drive, which might cause abrupt movement. This mode should only be used when it can be determined that any movement during disabling is very small. The EnablePositionBand (tolerance) is used to control the maximum permissible deviation from the disabled commanded position. If the axis moves less than the tolerance while disabled, the disabled commanded position is used and the axis snaps back. If the axis moves more than the tolerance while disabled, then the present position of the axis is used and the axis remains still while disabling. An example situation is an axis with a brake that can only be moved under control module power.

Tolerance in SETPOINT Mode

In-position band is a tolerance band used when the SETPOINT enable mode is the defined EnableMode. If the CURRENTVALUE enable mode is defined, in-position band has no effect.

If the axis is configured in SETPOINT mode, and the axis moves less than the in-position band distance after the axis is deactivated, the axis control module:

1. Retrieves the last commanded position that was issued before the axis was deactivated.

2. Commands the axis to move to this position when the axis is re-activated.

If the axis moves more than the in-position band distance, the module re-activates the axis by provisionally changing to CURRENTVALUE mode. The module:

1. Reads the position of the axis.

2. Commands the axis to remain at this position when the axis is re-activated.

This prevents the axis from moving more than the in-position band when the axis is re-activated in SETPOINT mode.