HTL input fault

What does 28803 mean?

The monitoring of the input signal configured for the HTL input has been triggered. This indicates a problem with the High-Threshold Logic input signal, potentially an unexpected pulse count or signal level.

• Loss of one or more phases (e.g., A, B, Z) of the HTL encoder signal due to a damaged cable or loose connector.
• Signal noise or electromagnetic interference causing spurious pulses on the HTL input, leading to an incorrect pulse count.
• HTL encoder power supply failure (e.g., 24VDC) or voltage sag below the minimum threshold, degrading the signal.
• Incorrectly configured pulse monitoring (e.g., minimum frequency, pulse count discrepancy) for the HTL input in drive parameters.
• Internal failure of the HTL encoder itself, producing an intermittent or incorrect signal.

Click steps to track your progress.

1. 1

   Measure the 24VDC supply voltage at the HTL encoder's power terminals (e.g., X5.1) to ensure it is within specified limits.

2. 2

   Using an oscilloscope, monitor the HTL A, B, and Z signals at the drive's input terminals (e.g., X5.2, X5.3, X5.4) for proper waveform and absence of noise.

3. 3

   Inspect the HTL encoder cable for physical damage, proper shielding, and secure connections at both the encoder and drive ends.

4. 4

   Verify the drive's parameters related to HTL input monitoring (e.g., minimum frequency threshold, number of pulses per revolution).

5. 5

   Swap the HTL encoder with a known good unit (if available) to differentiate between encoder failure and drive input issues.