5.1.3 When to calibrateWhen to calibrateThe system must be calibrated if any of the following situations occur.The resolver values are changedIf resolver values are changed, the robot must be recalibrated using the calibrationmethods supplied by ABB. Calibrate the robot carefully with standard calibration,according to information in this manual.The resolver values will change when parts affecting the calibration position arereplaced on the robot, for example motors or parts of the transmission.The revolution counter memory is lostIf the revolution counter memory is lost, the counters must be updated. SeeUpdating revolution counters on page 231. This will occur when:• The battery is discharged• A resolver error occurs• The signal between a resolver and measurement board is interrupted• A robot axis is moved with the control system disconnectedThe revolution counters must also be updated after the robot and controller areconnected at the first installation.The robot is rebuiltIf the robot is rebuilt, for example, after a crash or when the reach ability of a robotis changed, it needs to be recalibrated for new resolver values.Product manual - IRB 120 2273HAC035728-001 Revision: N© Copyright 2009-2017 ABB. All rights reserved.5 Calibration5.1.3 When to calibrate