Brake sequence fault

What does E.MB5 mean?

This brake sequence fault stops the inverter output due to a sequence error occurring during the operation of the brake sequence function (configured by Pr. 278 to Pr. 283). This protective feature is not active in the initial inverter status. It indicates a timing or logical error in the controlled braking process.

• Incorrect timing or state transition within the brake sequence parameters (Pr. 278 to Pr. 283) not matching mechanical brake characteristics.
• Failure of the external brake contactor or brake feedback switch to provide expected status within the defined sequence time.
• Mechanical binding or excessive wear in the motor brake assembly, preventing proper engagement/disengagement within the set time.
• Contamination or damage to the brake feedback switch (e.g., limit switch, proximity sensor) causing erroneous status signals to the inverter.
• Motor shaft encoder slip or malfunction, leading to an incorrect speed feedback during brake sequence monitoring.

Click steps to track your progress.

1. 1

   1. Verify the settings of brake sequence parameters Pr. 278 (Brake opening command time), Pr. 279 (Brake closing command time), Pr. 280 (Brake opening confirmation speed), Pr. 281 (Brake closing confirmation speed), Pr. 282 (Brake opening confirmation time), and Pr. 283 (Brake closing confirmation time). Adjust as needed to match actual mechanical brake operation.

2. 2

   2. Check the wiring continuity and resistance of the brake coil terminals (e.g., U1/V1/W1) and the brake feedback switch terminals for open circuits, shorts, or high resistance connections.

3. 3

   3. Monitor the actual speed feedback (e.g., from encoder on P1, P2 terminals) and the digital input status for the brake feedback switch (e.g., input terminal STO1, STO2) during a brake operation cycle using the inverter's monitor function.

4. 4

   4. Manually operate the mechanical brake and verify the physical movement and electrical feedback signal from the brake switch using a multimeter on its output contacts (NO/NC).

5. 5

   5. Measure the voltage supplied to the brake coil (e.g., 200V, 400V, 24VDC) at the brake terminal block to ensure it is within the manufacturer's specified range during the activation command.