Brake Setting
Holding brake is used to stop the unexpected movement of moving loads(e.g., falling under gravity) when the servo system is not activated (e.g., servo system is powered off), to prevent servo motor from moving unexpectedly due to its own weight or external force after being powered off.
Note:
- Holding brake is the non-powered action type special mechanism, which can't be used for braking, and can be used only when servo motor is in the stop state.
- Non-polarity of Holding brake coil;
- After servo motor stops, it shall switch off servo enable.
- When the motor with built-in Holding brake runs, the brake might make the clicking, that doesn't affect any function;
- When the brake coil is energized (the brake is ON), magnetic flux leakage may occur at shaft ends. When using the magnetic sensor near motors, please pay attention to the possibility of this situation.
Holding brake parameter setting
For applications with Holding brake, it must set Holding brake enable switch(P05.12) ON, and one of servo drive DO terminals must be configured to Function 17 (BK, Holding brake control), and ensure the valid logic for the corresponding DO terminal.
According to the current state of the servo drive, the working timing of the brake mechanism can be divided into two types: the normal state brake timing of the servo drive and the fault state brake timing of the servo drive.
| P05.12- Lock Holding brake switch | |
| Index - Subindex | 0x2005-0D |
| Data type | UINT16 |
| Accessibility | Readable/writable |
| Unit | - |
| Default | 1 |
| Min. | 0 |
| Max. | 1 |
| Setting and effective mode | Run settings/Effective immediately |
| Related mode | - |
| Note | - |
| Encoding | Name | Function name | Functions |
| 17 | BK | Holding brake control | Ineffective, the brake power supply is ON, the brake runs, motor is in the position stalled state; Effective, the brake power supply is OFF, the brake is cancelled, and motor can move; |
Servo drive normal state brake timing
Holding brake sequence in the normal state can be divided into such 2 situations as motor static and motor dynamic:
- Static: Motor actual speed is below 30rpm;
- Dynamic: Motor actual speed reaches 30rpm and above.
(1) Timing of brake holding when servo motor is stationary
When servo enable is switched from ON to OFF, if the current motor speed is lower than 30rpm, the drive would run according to static brake sequence;
After the brake output is set from OFF to ON, do not enter any position/speed/torque instruction within P05.13 time, or instructions would be lost or it would run improperly;
Being used in vertical axis, self-weight or external force of mechanical moving part may cause the slight movement of machine. When servo motor is stationary, the servo enable switches OFF, and the brake output immediately turns OFF, but within P05.14 time, the motor is still in the power-on state to prevent mechanical moving part from moving due to self-weight or external force.
- 1. When servo enable is ON, the brake output is set as ON; At the same time, the motor enters the power-on state;
- 2. Please refer to the relevant specification for delay time of action of Holding brake contact part;
- 3. From the brake output set as ON to inputing command, please leave an interval above P05.13 time;
- 4. When servo motor is static(motor speed below 30rpm), when servo enable is OFF, brake output is set as OFF at the same time. By P05.14, motor enters the delay of non-power-on state after brake output is set as OFF.
P05.13 Index code from the brake switch-off to receiving command delay(Stop state)
| P05.13 - From the brake switch-off to receiving command delay | |
| Index | 0x2005-0E |
| Data type | Uint16 |
| Accessibility | Readable/writable |
| Unit | ms |
| Default | 250 |
| Min. | 0 |
| Max. | 500 |
| Setting and effective mode | Run settings/Effective immediately |
| Related mode | - |
| Note | - |
P05.14 Index code of zero speed holding time of Holding brake switched on (Stop state)
| P05.14- Zero speed holding time for lock suction | |
| Index | 0x2005-0F |
| Data type | Uint16 |
| Accessibility | Readable/writable |
| Unit | ms |
| Default | 150 |
| Min. | 1 |
| Max. | 1000 |
| Setting and effective mode | Run settings/Effective immediately |
| Related mode | - |
| Note | - |
(2) Timing of brake holding during servo motor movement
When servo enable is switched from ON to OFF, if the current motor speed is higher than or equal to 30rpm, the drive will operate according to the motion brake sequence.
When the servo enable is set from OFF to ON, do not enter position/speed/torque command within P05.13 time, or commands will be lost or operates improperly;
While servo motor is moving, servo enable OFF occurs, and servo motor enters zero speed stop state, but Holding brake output can be set as OFF only if any of the following conditions are met. I. P05.16 time hasn't expired, but it has reduced the motor speed to P05.15; ⅱ. P05.16 time ends, but motor speed is still above P05.15.
Output of Holding brake ON change OFF then 50ms during the period, motor is still powered on and prevent mechanical parts from moving due to self-weight or external force.
- 1. When servo enable is ON, the brake output is set as ON; At the same time, the motor enters the power-on state;
- 2. Please refer to the relevant specification for delay time of actions of Holding brake contact part.
- 3, From Holding brake output as ON to input command, please set an interval above P05.13.
- 4. In the case of servo motor movement, when servo enable is OFF, it can set the delay of Holding brake output OFF after servo enable is OFF. It can be set through P05.15 and P05.16. After Holding brake outputs OFF, delay time is 50ms, then motor would enter the non-powered state.
P05.15 Holding brake power-on speed threshold
| P05.15 - Holding brake power-on speed threshold | |
| Index | 0x2005-10 |
| Data type | Uint16 |
| Accessibility | Readable/writable |
| Unit | rpm |
| Default | 30 |
| Min. | 0 |
| Max. | 3000 |
| Setting and effective mode | Run settings/Effective immediately |
| Related mode | - |
| Note | - |
P05.16 - Holding brake power-on speed threshold
| P05.16 - Holding brake power-on speed threshold | |
| Index | 0x2005-11 |
| Data type | Uint16 |
| Accessibility | Readable/writable |
| Unit | ms |
| Default | 500（ms） |
| Min. | 1 |
| Max. | 1000 |
| Setting and effective mode | Run settings/Effective immediately |
| Related mode | - |
| Note | - |
Servo drive fault status brake timing
According to stop modes, servo Errors are classified into Type 1 fault(referred to as NO.1) and Type 2 fault (referred to as NO.2). For details, see Chapter 5 Troubleshooting and Alarm. Holding brake sequence of servo drive in Error state can be divided into the following 2 situations:
(1) Type 1 fault occurs
The output condition of the brake DO is the same as the brake timing when the servo motor moves under normal state of the servo driver. That is, the brake output must meet any of the following conditions to be set to OFF:
- P05.16 time has not yet arrived, but the motor has slowed down to P05.15;
- P05.16 time has passed, but the motor speed is still higher than P05.15.
(2) Type 2 fault occurs
When the second type of fault occurs and the brake is enabled, the shutdown mode for the second type of fault is forced to be "zero speed shutdown, free running state".
At this point, the servo motor first stops at zero speed. When the actual speed of the motor is below 30rpm, the output condition of the brake DO is the same as the "brake timing when the servo motor is stationary in the normal state of the servo driver", that is, the brake output immediately becomes OFF, but the motor is still powered on during P05.14 time.