Cause : JOG right and JOG left signals active comes when both JOG right and JOG left signals active together. This means the drive received both command signal at same time.

A0923 alarm in Siemens Micromaster 420 (MM420) indicates that both JOG right and JOG left signals are active simultaneously. This condition is not allowed because it can cause conflicting commands to the drive.

Here’s how to diagnose and address this issue:

1. Check Control Wiring:

   • Inspect the wiring of the JOG right and JOG left control signals. Ensure that there are no shorts or incorrect connections causing both signals to be active at the same time.

2. Review Control Logic:

   • Check the control logic used to generate the JOG signals. Ensure that the logic correctly prevents both JOG right and JOG left signals from being active simultaneously.

3. Inspect Control Devices:

   • Verify that the control devices (such as switches, PLC outputs, or relay contacts) used to generate the JOG signals are functioning correctly. Ensure that they are not stuck or malfunctioning, causing both signals to activate.

4. Drive Parameters and Settings:

   • Review the drive parameters related to JOG control. Ensure that the settings are correctly configured for your application. Key parameters to check include:
     • JOG frequency
     • JOG acceleration time
     • JOG deceleration time

5. Eliminate Signal Overlap:

   • Ensure that there is no overlap in the timing of the JOG right and JOG left signals. Implement interlocking logic in the control system to prevent both signals from being active at the same time.

6. Test Operation:

   • After making any necessary adjustments, test the operation of the JOG control to ensure that only one signal is active at a time and that the drive responds correctly to the JOG commands.