Please refer to the specification sheet.

About Maximum Torque

This is the value listed as Max. Torque in the specification sheet.
It indicates the torque level at which a load is applied to the servo for approximately one second at room temperature and the unit is confirmed not to fail.

About Rated Torque

This is the value listed as Rated Torque in the specification sheet.
It refers to the load used in the endurance test described in the specification sheet.
However, if the servo is operated under severe motion conditions during the endurance test or in an environment where heat dissipation is difficult, the temperature may rise excessively and stable operation may not be possible.

When using the servo, please ensure that the load remains at or below the rated torque and confirm that the temperature in the actual operating environment does not rise excessively.

An IPx7 servo has been verified to remain unaffected when immersed in water at a depth of 1 meter for 30 minutes in new condition.
However, failure may occur if the conditions differ, such as forceful immersion, use in non-fresh water, or exposure to flowing water.

Yes. However, water may enter the unit if it is exposed to strong water flow from a hose, shower nozzle, or similar source.

It ranges from DC 4.8 V to 48 V, depending on the servo model.

It is secured with screws using the mounting holes. However, the mounting position and shape vary depending on the model. You can see how to mount the BLA21 series in this video.

As a general guideline, the service life can be estimated from the servo operating time based on the MTTF (Mean Time To Failure) under the operating conditions specified in the specification sheet. Please note that the estimated value may vary significantly if excessive force is applied to the servo.

If the power supply voltage is lower than the reference voltage shown in the specification sheet, or if the wiring is thin and long, the maximum torque of the servo may decrease.

Torque and current are correlated. Please contact us for details.

This depends on the servo specifications and interface.
PWM: Not supported.
S.BUS and S.BUS2: By using our SBS-01S, angle and current can be obtained through our protocol.
rs485 and DronCAN v1: Servo information can be obtained using commands.

The availability and settings vary depending on the type of servo. Please contact us for details.

PWM, S.BUS (Futaba’s proprietary serial communication standard), rs485, and DroneCAN are supported.
Supported communication standards vary by model, so please refer to the product list.

DroneCAN is a higher-layer protocol based on the CAN 2.0B protocol. For details on the DroneCAN protocol, please refer to the official DroneCAN website.

The DroneCAN protocol specification is available here.

Yes. You can easily check them using DroneCAN Tools.
To connect a DroneCAN-compatible servo to a PC, please use the starter kit.

Yes. Connect the DroneCAN-compatible servo to a PC using the starter kit  and update it with the dedicated updater.

Either can be used, but we recommend using GetSet (Default data type ID=11).
GetSet (Default data type ID=11) allows access to all servo functions. ArrayCommand (Default data type ID=0x1010) has more limited operation, but it enables servo motor control using a common command regardless of manufacturer.

DroneCAN Protocol Specification

An example of driving a DroneCAN-compatible servo 90 degrees clockwise is shown below.

1. If the servo node ID is 0, perform dynamic node ID allocation.
2. 「GetSet」Send an angle command using either the “GetSet” or “ArrayCommand” command.

The reason it only rotates within ±180 degrees is considered to be that the default values for the operating angle limits CW/CCW are 179.9 degrees and -180.0 degrees. By expanding the operating angle limits according to the procedure below, the servo can rotate within the configured operating angle range. How to drive beyond ±180 degrees with angle commands

How to drive beyond ±180 degrees with angle commands

1. Set the operating angle limits RCW/CCW [0x38]/[0x39] to values greater than ±180 degrees.
2. Set the desired angle in the command angle [0x00].

The node ID is a unique number used for communication between nodes, and it is used in the CAN ID of all commands. The same node ID cannot be assigned to multiple nodes. The servo ID refers to the actuator ID on page 9 of the communication interface specification and is used with uavcan.equipment.actuator.ArrayCommand. The same servo ID can be set for multiple servos, and up to 15 servo IDs can be specified in a single message.

DroneCAN Protocol Specification

For changing the node ID, please follow the steps below:

1. Use the GetSet command to write the desired node ID value to UAVCAN node ID [0x46].
2. Execute ROM write.
   Write 1 to ROM write [0x12] using the GetSet command, or
   Send the ExecuteOpcode command.
3. Restart the unit.
   Turn the servo power OFF and then ON, or
   Write 1 to restart [0x11] using the GetSet command, or
   Send the RestartNode command.

Current angle [0x08], current speed [0x09], current torque [0x0A], current temperature [0x0B], current voltage [0x0C], and abnormality summary [0x18] are updated internally by the servo every 1 ms.

The behavior when a PWM communication error occurs during PWM angle control is determined by the following parameter settings.
You can select from three modes: brake, hold, or free.

• Communication timeout behavior [0x26]
• Communication timeout determination time [0x27]

During a PWM communication error, CAN status values such as temperature and voltage will indicate normal values.
However, if a CAN communication error occurs while acquiring CAN status, the status values cannot be obtained from the servo.

The CAN bus baud rate is available only at 1 Mbps.

Some models allow a rotating shaft to be attached on the side opposite the output shaft. Using this configuration helps improve frame rigidity. For details, please watch the video here. The following servo models support installation of a rotating shaft:

• BLA21-06U-A01
• BLA21-12U-A01
• BLA21-28U-A01

Yes, it is possible to rotate a single shaft using two servos.
However, due to individual differences between servos, using two servos does not double the torque. Please note the following two points when setting this up.

The home positions of the two servos will not match exactly due to mounting errors and other factors, so adjustment is required.

• With command-based control such as DroneCAN, the angle of each servo can be identified through signals, making home position adjustment easier.
• With S.BUS or PWM, adjustment must be made using PC software or through the mechanical setup.

Because there are individual differences in the operating angle accuracy of the two servos, the motion may become misaligned. This can be mitigated by settings such as deadband, but doing so will reduce servo motion performance. To address this issue, we recommend using servos with high angle accuracy.

• RS servos undergo angle calibration before shipment, so they offer relatively high accuracy.
• Servos with non-contact angle sensors (such as BLA15 and BLA21) are not calibrated, but the sensors themselves provide high accuracy.
• Many PWM and S.BUS servos do not offer high angle accuracy and are often at the RC servo level.

Yes. The noise is caused by the feedback control inside the servo.
However, if the sound is different from usual, such as suddenly becoming louder, there may be a problem. In that case, please contact us.

Fabricating a horn that properly engages with the serration (gear-like spline) on the servo output shaft is difficult.
Please modify the servo horn itself to accommodate your application.

Please evaluate and determine this based on your actual operating environment.

We recommend checking the following two points in particular:

• Communication reliability:Depending on the cable length, routing, and whether noise countermeasures are in place, communication signals may degrade or drop out.
• Voltage drop:Electrical resistance in the cable may cause a voltage drop, which could lead to the servo motor or other devices connected to the bus line powering off.

Yes, some products ^※can be controlled from a PLC.

Please connect termination resistors at the end nodes. Termination resistors are not built into the servo.
Please also refer to the connection information for our starter kit for DroneCAN-compatible servos.

We recommend connecting termination resistors at the end nodes, although depending on the operating environment, it may also be possible to omit them. Termination resistors are not built into the servo.

Yes, we recommend adding a capacitor.This is especially effective when the servo power supply has limited margin or when the power wiring is long. Better results can be achieved by connecting a capacitor of 1,000 μF or more as close to the servo as possible.