Recovering from servo errors

About this topic

This topic explains how to recover from servo errors.

Causes of servo errors

A servo system controls the robot’s motions. The servo cuts power to the robot if it encounters resistance to movement that is slightly higher than that expected from the inertia of the robotic arm holding a labware. When the power is cut, a servo error is generated.

Most servo errors occur when the labware being carried crashes into another labware that is on a device.

Procedure

To recover from a servo error:

1	Check the system to determine the cause of the collision and remove the obstruction. For example, it might be a labware from a previous run.

2	Check the labware that is held by the robot to make sure it is not damaged and that its contents are not spilled.

3	Make sure the labware did not move in the robot gripper during the collision.

4	If the labware has not moved in the robot gripper and was not damaged during the collision, in the error message dialog box, click one of the following:

 

Selection	Description
Diagnostics	Opens the device diagnostics dialog box. Note: This selection is available only when you are in the middle of a protocol run and not while you are already in the device diagnostics software.
Retry	Attempts to restart the current command or task in the run.
Ignore and continue	Ignores the current command or task and continues to the next command or task in the protocol sequence.
Abort	Aborts the current command or task in the run. Select Abort if you have determined that the protocol run is not recoverable.

5	If the labware has moved during the collision or was damaged, in the error message dialog box, click Diagnostics and move the labware manually:

a	Move the robot to a position that is easy for you to access.

b	While holding the labware with your hand, click Open in the DDR Diagnostics Jog/Teach tab to release the labware to your hand. The robot releases the labware.

c	Place the labware at the destination location manually.

d	Close DDR Diagnostics.

e	Click in the next error message dialog box, and then click Ignore and continue.

6	If the crash was severe, home the robot.

Related information

 

For information about...	See...
Opening the robot grippers	Opening and closing the robot grippers
Homing the robot	Homing the robot and grippers
Verifying teachpoints	Verifying teachpoints
Reporting problems	Reporting problems