Cause : Command pulse sealer error comes when he command pulse is larger than 500 kpps at the entrance of the position error counter. The scale ratios set by Pr46 through Pr4B (numerator of 1st to 4th command scale) are not correct.

"alarm 27" in panasonic servo drive indicate "Command pulse sealer error". This means an issue related to the command pulse signals being sent to the servo drive. This error suggests that there may be problems with how the drive is receiving, interpreting, or executing these command pulses, which are critical for controlling the motor's position or speed.

Troubleshooting Steps:

1. Check Command Pulse Source:

• Signal Source Integrity: Verify that the device or controller sending the command pulses to the servo drive is functioning correctly. Ensure that it is generating pulses as expected and that these pulses are within the correct specifications.
• Pulse Signal Type: Ensure that the command pulse type (e.g., pulse + direction, quadrature) matches the configuration of the servo drive.

2. Inspect Wiring and Connections:

• Wiring Integrity: Check the wiring between the pulse source and the servo drive. Ensure that all connections are secure and free from damage or interference.
• Connector Condition: Inspect the connectors for any signs of wear, corrosion, or loose connections that could affect the pulse signals.

3. Review Drive Parameters:

• Command Pulse Settings: Review the servo drive’s parameters related to command pulse input, such as pulse type, pulse input filter settings, and pulse multiplication/division factors. Ensure these settings match the requirements of your application and the pulse source.
• Signal Filtering: If the drive allows, adjust the filtering or debounce settings for the command pulse input to help reduce the effects of noise or irregularities in the pulse signal.

4. Check for Electrical Noise:

• Noise Sources: Ensure that the command pulse cables are routed away from sources of electrical noise, such as power lines, high-frequency equipment, or motors. Electrical noise can corrupt the pulse signals and cause errors.
• Shielded Cables: Use shielded cables for the command pulse signals if possible, to minimize the impact of electrical noise.

5. Inspect the Servo Drive:

• Drive Diagnostics: Run any available diagnostics on the servo drive to check for internal issues that could affect how it processes command pulses.
• Firmware Update: Check if there is a firmware update available for the servo drive that might address issues with command pulse handling.

6. Test with an Alternate Pulse Source:

• Alternate Source Testing: If possible, test the servo drive with an alternative command pulse source to determine if the problem lies with the pulse source or the drive itself.

7. Error Reset and Monitoring:

• Reset the Error: After addressing the potential causes, reset the command pulse sealer error in the servo drive.
• Operational Monitoring: Monitor the system during operation to ensure the error does not recur, particularly during scenarios where the command pulse signals are critical.