OT0506

Press SYSTEM > CURRENT (POSITION screen), verify A-axis Machine coordinate value. Compare against parameter 1320 (negative limit) and 1321 (positive limit) for A-axis.

Press SYSTEM > PARAM, check bit 1 of parameter 1006 (ROT axis enable). If ROT is OFF, parameters 1320/1321 treat A-axis as linear. For rotary, enable ROT bit or adjust limits to ±9999.999 degrees.

If parameter 1321 A-axis value is too restrictive, adjust positive software limit. For continuous rotation rotary tables, set parameter 1320=-9999.999 and 1321=9999.999, then set bit 0 of parameter 1006 (LIM) to 0 to disable software OT check.

Verify mechanical limits and application requirements before disabling software limits

If returning to work coordinate, perform manual handle jog in negative A direction to clear position, then execute G28 A0 or reference return (G28 H0 for 0i/30i/31i/32i) to reset machine coordinates.

Press SYSTEM > DIAGNOSIS > PARAM and view diagnostic number 300 (DGN 300). Check bit assignment for A-axis +OT signal status. Bit should be 0 when not at limit. If bit=1, hardware limit switch is active.

Do not force axis movement into the limit switch - mechanical damage may occur

Manually rotate A-axis table in negative direction using handwheel (MPG) override. Monitor DGN 300 until +OT bit clears to 0. If switch does not clear, inspect limit switch X14/X15 wiring, dog position, and switch mounting on A-axis rotary unit.

Check stored stroke limit (deceleration dog) position. Press SYSTEM > PARAM, verify parameter 1320/1321 stored stroke limits match physical dog positions. Adjust dogs or parameters so stored stroke activates 5-10mm before hardware +OT switch.

After clearing hardware limit, execute reference return sequence (G28 H0 A0 for incremental, or manual REF RETURN mode). Verify A-axis zero return completes and parameter 1815 (reference position) matches expected machine zero for rotary axis.

Press SYSTEM > DIAGNOSIS, check DGN 300 for A-axis feedback signals and DGN 400 for A-axis position error. Verify encoder battery voltage (DGN 311 or amplifier LED display). Alpha servo: check 7-segment LED on amplifier for code 1 (normal) or error codes.

Check parameter 1815 (A-axis reference position), parameter 1850 (A-axis absolute position), and current machine position consistency. If values are erratic or >360 degrees difference on rotary axis, perform encoder battery replacement and absolute position re-establishment.

Encoder battery replacement requires re-setting absolute reference position - record current position before battery change

Verify A-axis amplifier and motor encoder cable connections (feedback cable connector at motor and amplifier CNA/CNB). Inspect for damage, loose pins, or contamination. Check amplifier LED for alarm codes: A6 (encoder error), A7 (overheat), or A9 (overload).