E-27Â Encoder Wire Break fault in Toshiba drive
E-27 Encoder Wire Break (Hardware) fault in Toshiba drive
Description E-27 is distinct from E-13 (Speed Error). E-13 is a logical calculation ("Speed is wrong"). E-27 is a physical hardware check. The encoder option card monitors the voltage levels of the A, B, and Z channels. If the differential voltage (A vs A-not) drops to zero, or if the "Z" (Marker) pulse is missing for several rotations, the card assumes the physical wire is cut or the encoder bulb has burned out. Causes
1. Severed Cable: The encoder cable was cut or disconnected.
2. Missing Pull-Up: If using an Open Collector encoder, the external pull-up resistors are missing or voltage is too low.
3. Power Supply: The encoder requires 5V but is fed 12V, or vice-versa, causing signal degradation.
4. Z-Pulse Failure: The application requires a Z-pulse for positioning, but the installed encoder is a basic A/B quadrature type without a Z-channel. Solution Check the encoder wiring at the option card terminal block. Look for loose strands or shielding touching the signal pins.
Measure the voltage between A and 0V while slowly turning the motor shaft by hand. You should see the voltage toggle (e.g., 0V to 5V). If it stays constant, the encoder output driver is blown.
Verify the "PG Type" parameter. If the drive expects a "Line Driver" (differential) signal but you wired a "Complementary" or "Open Collector" encoder, the hardware detection will trigger E-27. Ensure the DIP switches on the PG option card match the voltage of the encoder (5V vs 12V/15V).
Description E-27 is distinct from E-13 (Speed Error). E-13 is a logical calculation ("Speed is wrong"). E-27 is a physical hardware check. The encoder option card monitors the voltage levels of the A, B, and Z channels. If the differential voltage (A vs A-not) drops to zero, or if the "Z" (Marker) pulse is missing for several rotations, the card assumes the physical wire is cut or the encoder bulb has burned out. Causes
1. Severed Cable: The encoder cable was cut or disconnected.
2. Missing Pull-Up: If using an Open Collector encoder, the external pull-up resistors are missing or voltage is too low.
3. Power Supply: The encoder requires 5V but is fed 12V, or vice-versa, causing signal degradation.
4. Z-Pulse Failure: The application requires a Z-pulse for positioning, but the installed encoder is a basic A/B quadrature type without a Z-channel. Solution Check the encoder wiring at the option card terminal block. Look for loose strands or shielding touching the signal pins.
Measure the voltage between A and 0V while slowly turning the motor shaft by hand. You should see the voltage toggle (e.g., 0V to 5V). If it stays constant, the encoder output driver is blown.
Verify the "PG Type" parameter. If the drive expects a "Line Driver" (differential) signal but you wired a "Complementary" or "Open Collector" encoder, the hardware detection will trigger E-27. Ensure the DIP switches on the PG option card match the voltage of the encoder (5V vs 12V/15V).
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