3136

Common Causes

• DD encoder gap out of tolerance (too narrow or too wide) between sensor and scale
• DD encoder sensor tilted (inclination error) relative to the scale
• Contamination or damage on the absolute position track causing code/check errors
• Communication failure between the DD encoder and the control
• DD encoder unit itself defective

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XX bit7 = Error flag — set when an error is present; code XX bit6 = Absolute position sensor margin warning; code XX bit5 = Gap warning — steady means gap too small, toggling means gap too large; code XX bit4 = Inclination warning — steady means CCW tilt too large, toggling means CW tilt too large; code XX bit3 = Encoder is in auto-set mode; code XX bit2 = Communication error detected (toggles on detection); code XX bit1,0 = Error bit number within the absolute position code; code YY=01 = Stop command has stopped
2. 2Read the code on screen and branch on YY: 42 means the sensor gap is too narrow, 43 too wide, 40/41 an inclination error, 3E/3F absolute position sensor/code errors, 02 a control parameter error, 0D excessive speed, 0E a synchronization error.
3. 3For gap codes (42/43) or inclination codes (40/41): with power locked out, inspect the DD encoder mounting and measure/adjust the sensor-to-scale gap and alignment per the encoder's installation spec.
4. 4For absolute position code errors (3E/3F): clean the encoder scale and sensor head of oil, coolant, and chips, and check the scale for scratches.
5. 5For communication-related indications (XX bit2 toggling, YY=21): inspect the DD encoder cable and connectors for damage, looseness, or oil ingress and reseat them.
6. 6Check the XX status byte: bit6 warns of low absolute position sensor margin and bit5/bit4 give gap and inclination warnings — address these before they become hard errors.
7. 7If the encoder is clean, correctly gapped, and the cabling is good but the alarm remains, replace the DD encoder; if it still returns, record the alarm number, code, and object and contact Okuma service.