Advance Preparation

Before using current limiting function, following settings must be performed.

Required Settings

Tip Payload Specification

Specify the exact mass of payload and payload center of gravity of the tip. Set values corresponding to a hand and a work used for the mass of payload [g], the payload center of gravity X [mm], the payload center of gravity Y [mm], and the payload center of gravity Z [mm]. If the mass changes during chucking or unchucking a work, use PayLoad command to change the setting.

Gravity Offset Specification (for 6-axis robot only)

Be sure to enable the gravity offset specification when current is limited. Otherwise, an error may occur. To enable the gravity offset, use the pendant to set the enabling/disabling gravity offset setting to 1.
Though GrvCtrl command may also be used to enable/disable the gravity offset, the robot may present a slight movement while switching between the enabled state and disabled state. We recommend to use the configuration of the pendant to set the enabling/disabling gravity offset setting to 1 and call GrvCtrl once in the initialization program.

Settings Performed According to Circumstances

Gravity Offset Compensation

The difference between the setting of the mass of payload of the tip and the actual mass of payload may present an error in the gravity balance based on the gravity offset. When a smaller current limit is set to an axis where gravity applied, the robot may fall toward the direction of gravity.
The gravity offset compensation function compares the torque at the stationary state of your robot and the gravity offset torque to compensate the error. When setting the current limit to 30% or less for an axis where gravity applied, always set the gravity offset compensation. Execute GrvOffset to have compensation value calculated when the robot is stopping.
The value obtained is for the posture when GrvOffset is executed.
Be sure to execute GrvOffset again when the posture deviates largely from that when compensated.
Executing GrvOffset command may generate a compensation value including an error when an external force such as a contact is applied to the robot. Run GrvOffset command when the external forces (except for gravity) are not present.

Allowable Deviation Specification

If an external force is applied while current is limited, joint will rotate toward the direction of the force. This will increase the deviation of the angle of the joint and may cause an error. If this is the case, use Eralw command to set the allowable deviation specification. The function checking deviation is provided for safety. Do not extend the range unnecessarily.