Data Sheet

2/23/2018 XH-430-V350
http://support.robotis.com/en/product/actuator/dynamixel_x/xh_series/xh-430-v350.htm 9/15
Note : Ka is an Anti-windup Gain that cannot be modified by users. For more details about the PID controller and Feedforward controller, please refer to the below websites.
http://en.wikipedia.org/wiki/PID_controller
https://en.wikipedia.org/wiki/Feed_forward_(control)
Bus Watchdog (98, Available after Firmware version 38)
Bus Watchdog (98) is a safety device (Fail-safe) that stops the Dynamixel if the communication between the controller and Dynamixel communication (RS485, TTL) is disconnected due to an unspecified
error.
Communication is defined as all the Instruction Packet in the Dynamixel Protocol.
Values Description
Unit 20[ms]
Range
0 Deactivate Bus Watchdog Function, Clear Bus Watchdog Erro
1 ~ 127 Activate Bus Watchdog
-1 Bus Watchdog Error Status
The Bus Watchdog function monitors the communication interval (time) between the controller and Dynamixel when Torque Enable (64) is '1'.
If the measured communication interval (time) is larger than Bus Watchdog (98), the Dynamixel will stop. Bus Watchdog (98) will be changed to '-1' (Bus Watchdog Error).
If the Bus Watchdog Error screen appears, the Goal Value (Goal PWM(100), Goal Current(102), Goal Velocity(104), Goal Position(116)) will be changed to read-only-access.
Therefore, when a new value is written to the Goal Value, a Range Error will be returned via the Status packet.
If the value of Bus Watchdog (98) is changed to '0', Bus Watchdog Error will be cleared.
Note: For details of Range Error, please refer to the protocol of the e-Manual.
The following are examples of the operation of the Bus Watchdog function.
① After setting the operating mode (11) to speed control mode, change the Torque Enable (64) to '1'.
② If '50' is written in the Goal Velocity (104), the Dynamixel will rotate in CCW direction.
③ Change the value of Bus Watchdog (98) to '100' (2,000 [ms]). (Activate Bus Watchdog Function)
④ If no instruction packet is received for 2,000 [ms], the Dynamixel will stop. When it stops, the Profile Acceleration (108) and Profile Velocity (112) are applied as '0'.
⑤ The value of Bus Watchdog (98) changes to '-1' (Bus Watchdog Error). At this time, the access to the Goal Value will be changed to read-only.
⑥ If '150' is written to the Goal Velocity (104), Range Error will be returned via Status Packet.
⑦ If the value of Bus Watchdog (98) is changed to '0', Bus Watchdog Error will be cleared.
⑧ If “150” is written in the Goal Velocity (104), the Dynamixel will rotate in CCW direction.
Goal PWM (100)
In case of PWM Control Mode, both PID controller and Feedforward controller are deactivated while Goal PWM(100) value is directly controlling the motor through an Inverter. In other control modes, this
value is used to limit PWM value. This value cannot exceed PWM Limit(36). Please refer to the Gain section in order to see how Goal PWM(100) affects to different control modes.
Values Description
Range 0 ~ PWM Limit(36) Initial Value of PWM Limit(36) : ‘885’
Goal Current (102)
In case of Torque Control Mode, Goal Current(102) can be used to set a target current. This value sets a limit to current in Current-based Position Control mode. This value cannot exceed Current Limit(38).
Values Description
Unit about 1.34[mA] All current related Data uses the same unit
Range -Current Limit(38) ~ Current Limit(38) -
Note : Applying high current to the motor for long period of time might damage the motor.
Goal Velocity (104)
In case of Velocity Control Mode, Goal Velocity(104) can be used to set a target velocity. This value cannot exceed Velocity Limit(44). For now, Goal Velocity(104) is used for target velocity, but this value is
not used to limit the velocity.
Values Description