Position & mastering
Robot loses its position or mastering overnight
If the robot comes up having forgotten where its axes are, the encoder backup batteries are the first thing to suspect.
Most likely causes
Dead or disconnected encoder backup battery (BZAL)
The battery backing up the pulse coders' absolute position data is empty or not connected, so the robot has lost track of where its axes are. If BZAL shows up right after a fresh battery install, suspect the battery-to-encoder cable inside the robot has come loose or is grounded.
Low battery warning that was ignored (BLAL)
BLAL is the warning shot before BZAL: battery voltage has dropped below the allowable minimum but position data isn't lost yet. Left alone, the next event is BZAL, lost position data, and a mastering job.
Rotation counter miscount (RCAL)
The pulse coder's built-in rotation counter miscounted, so its own bookkeeping is suspect. This can be a grounding or noise issue. If it appears alongside SRVO-068, SRVO-069, or SRVO-070, it may not be a real alarm and those communication alarms are the story to chase.
Pulse reference not yet established (SRVO-075)
After a BZAL event and battery/encoder work, the absolute encoder hasn't re-established its position reference. This is expected during recovery and must be cleared before mastering will take.
Where to start
- Read the active and history alarms and identify which code is present: SRVO-062 (BZAL), SRVO-065 (BLAL), SRVO-063 (RCAL), or SRVO-075 (pulse not established).
- If SRVO-063 is present, check the history for SRVO-068, SRVO-069, or SRVO-070 first, since those communication alarms may be the real cause.
- Battery and encoder work here points to lost position data and re-mastering, which is qualified maintenance work. Follow the matching alarm-code page for the recovery sequence.
- See SRVO-062 for the BZAL recovery sequence, and expect SRVO-075 on the next power-up as part of that recovery.
Related alarm codes
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