Absolute value encoder initialisation error at X8

What does Sd7 mean?

The absolute value encoder at X8 has an initialisation error, is defective, or is not sending data. This may also occur if the encoder constant (C0420) for C0025=309 is altered. An uninitialised encoder can lead to uncontrolled drive movements.

• Absolute value encoder power supply (e.g., 24VDC) at X8 is missing or unstable, preventing the encoder from booting up.
• Communication link (e.g., SSI, EnDat, Hiperface) between the absolute encoder and X8 input is interrupted or shorted.
• Encoder constant (C0420) configured for C0025 = 309 (absolute encoder) is incorrect, causing a data interpretation error.
• Internal fault within the absolute encoder, preventing it from initializing or sending valid position data.
• Loose or corroded connections at the X8 terminal block or the encoder's motor-mounted connector.

Click steps to track your progress.

1. 1

   Power off the drive, disconnect the encoder cable from X8, and measure the encoder power supply voltage at the X8 terminals with power on.

2. 2

   Inspect the absolute encoder cable for physical damage, continuity, and correct pinout for the specific communication protocol (e.g., SSI clock/data).

3. 3

   Verify parameter C0025 is set to 309 for absolute encoder, and C0420 (encoder constant) matches the encoder's specified resolution/turns.

4. 4

   Check the encoder's diagnostic LEDs (if present) for any fault indications during power-up or operation.

5. 5

   Ensure the encoder is properly mechanically mounted and aligned, as some absolute encoders require correct initial physical positioning.

6. 6

   Cycle power to the encoder and drive in sequence, then initiate an encoder re-initialization routine via the drive's keypad or software.