Mastering & calibration
Single-Axis Mastering a FANUC Robot (R-30iB)
Re-establishes the zero reference on a single FANUC R-30iB axis after mastering data is lost, such as following a Pulsecoder or motor change on one joint.
Confirm the scope is a single axis
Single axis mastering applies when the mastering data of one axis (or its interaction pair) was lost, for example from a drained Pulsecoder backup battery or a Pulsecoder exchange. Confirm the other axes still read correctly so you only touch the joint that needs it. If several unrelated axes lost mastering, treat each affected axis on its own merits.
Secure the cell before you start
Clear all other people from the work envelope and keep the cell secured while mastering, because you'll be jogging and possibly releasing a brake. Only a qualified technician should be inside operating the pendant. Apply your site's lockout and access controls appropriate to the work.
Verify $MASTER_ENB is set to 1
The single axis mastering procedure requires system variable $MASTER_ENB set to 1 (in the maintenance flow a value of 1 or 2 enables the MASTER/CAL menu). Check it on the SYSTEM Variables screen before continuing. This gate keeps mastering out of routine operator hands.
Clear any Pulse-not-established warning first
After a BZAL or CMAL event the controller posts SRVO-075 Pulse not established, and mastering can't run until the absolute position is established. Reset the alarm, then jog the affected axis about one motor revolution until SRVO-075 stops recurring. Mastering also cannot proceed until the axis has rotated enough to establish a pulse.
Open the MASTER/CAL screen
Press [MENU], select "0 - NEXT -", then select "6 SYSTEM". Press F1 [TYPE], then choose "Master/Cal" from the screen change menu. The Master/Cal screen lists FIXTURE POSITION MASTER, ZERO POSITION MASTER, QUICK MASTER, QUICK MASTER FOR SINGLE AXIS, SINGLE AXIS MASTER, SET QUICK MASTER REF, and CALIBRATE.
Select SINGLE AXIS MASTER
Choose "5 SINGLE AXIS MASTER" to open the single axis mastering screen. It shows a row per axis (J1 to J6 plus any extended axes) with columns ACTUAL POS, MSTR POS, SEL, and ST. This is the screen where you pick the one axis and give it a reference.
Read the four columns
ACTUAL POS is the current joint angle in degrees; MSTR POS is the mastering position you'll specify for the target axis, usually 0 degrees. SEL is set to 1 for the axis being mastered and is otherwise 0. ST shows completion state: 0 means data was lost and mastering is needed, 1 means lost with only the interaction axis done, and 2 means mastering is complete.
Check for an interaction axis
Some joints form an interaction pair, so mastering one influences the other and both must be done at the same time (for example J2/J3, or J4/J5/J6 on many models). Consult the model's interaction-axis table to confirm. On newer software the screen also displays the axis numbers you must select together if you leave one out.
Set SEL to 1 for the target axis
Move the cursor to the SEL field of the axis you want to master and enter 1, leaving every other axis at 0. You can set SEL on one axis at a time, or on the paired axes together when an interaction pair requires it. Setting SEL only on the chosen axis keeps the rest of the arm's mastering intact.
Jog to the mastering position
Jog the robot so the selected axis sits at its known reference, aligning the zero-position witness marks or seating the mastering fixture for that joint. Turn off the brake control on the manual brake screen only if the position requires it. A released brake can let the axis drop under gravity, so before releasing it a qualified technician must mechanically block or support that axis so it cannot fall; keeping clear is not a substitute for physical support.
Enter the mastering position value
In the MSTR POS field for the selected axis, key in the axis angle that matches the reference you jogged to, which is usually 0 degrees but can be another value the mechanical manual specifies (for example 90 for a fixture at 90 degrees). Enter the value for each selected axis of an interaction pair. Double-check the number against the manual before executing.
Execute the mastering
Press F5, EXEC to perform the single axis mastering. The controller sets SEL back to 0 and updates ST to 1 or 2 for the affected axis, confirming the reference was recorded. If ST stays at 0, the mastering did not take and you should recheck SEL, the pulse condition, and the entered value.
Return and calibrate
Press [PREV] to go back to the Master/Cal screen. Select "7 CALIBRATE" and press F4, YES so the controller recomputes joint angles from the new mastering data. Calibration also runs automatically each time the controller powers up.
Finish and cycle power
Press F5, DONE after calibration to close out the procedure, and restore the brake control to its original state if you released it. Cycle the controller power so calibration is applied cleanly on start-up. The pendant should now report the corrected position for the mastered axis.
Verify against the witness marks
After mastering, check that it was done correctly using the zero-position (witness) mark before trusting the result. Then confirm the robot and the cell behave as expected, running any motion at T1 low speed first. Return to production speed only once the mastered axis tracks correctly.
What can go wrong: lost pulse or counter alarms
SRVO-062 BZAL means the Pulsecoder backup battery was empty or disconnected and absolute position was lost, so after PULSE RESET and a power cycle you'll master again; SRVO-065 BLAL warns the battery is low before that point. SRVO-063 RCAL flags an abnormal Pulsecoder rotation counter and calls for the underlying grounding or motor fault to be fixed. Address the root cause rather than resetting and running to keep production up.
What can go wrong: mismatch or residual error after mastering
If the pulse count at power-on differs from what was recorded, the arm can come up mis-positioned after a Pulsecoder or battery change, or after a SYSMAST.SV loaded from another position, so verify the pendant position and re-master if it's wrong. If the arm still looks off, SRVO-310 ABC Unexpected Motion points to mastering data that's incorrect or executed at the wrong position. Never defeat or mask these alarms; correct the mastering instead.
Common questions
- How long does this procedure take?
- Single-Axis Mastering a FANUC Robot (R-30iB) is rated Advanced and takes about 45 minutes across 17 steps.
- What tools do I need?
- You will need Teach pendant, Zero-position (witness) marks or a mastering fixture for the target axis, Manual brake-release control screen access, Robot mechanical unit manual for the specific model (for the accurate mastering position).
- What should I do before starting?
- The technician is trained and qualified to run the MASTER/CAL screen, which is not usually displayed for general operators. You know which single axis lost its mastering and why (for example a Pulsecoder or motor replacement, or a BZAL battery fault on that joint). System variable $MASTER_ENB is set to 1 so the mastering menu is available. Any SRVO-075 Pulse not established warning on the target axis has been cleared first. For models that use Gravity Compensation by default, tentative mastering has already been performed on all axes. You have the robot model's interaction-axis relationship so you know whether the target axis must be mastered together with its pair.
- What is the first step?
- Confirm the scope is a single axis. Single axis mastering applies when the mastering data of one axis (or its interaction pair) was lost, for example from a drained Pulsecoder backup battery or a Pulsecoder exchange. Confirm the other axes still read correctly so you only touch the joint that needs it. If several unrelated axes lost mastering, treat each affected axis on its own merits.