CPB CANopen Technical Manual

Clock-direction mode


In clock-direction mode, the motor is operated via two inputs by a higher-level positioning controller with clock and direction signal. On each clock signal, the motor moves one step in the direction corresponding to the direction signal.


The following data apply for every subtype of the clock-direction mode:

  • The maximum frequency of the input pulse is 1 MHz; the ON pulse should not be less than 200 ns.

  • The demand position resulting from the input pulses is updated cyclically; the cycle time corresponds to the Interpolation Time Period (60C2h). The input pulses that arrive within a cycle are collected and buffered in the controller.
  • The steps are scaled using objects 2057h and 2058h. The following formula applies here:

    The "step size per pulse" value is set to 128 (2057h=128 and 2058h=1) ex works, which corresponds to a quarter step per pulse. A full step is the value "512", a half step per pulse corresponds to "256", etc.


    For a stepper motor with 50 pole pairs, 200 full steps correspond to one mechanical revolution of the motor shaft.

    In clock-direction mode, the BLDC motors are also handled as stepper motors by the controller. This means that for a BLDC motor with, e.g., 3 pole pairs, 12 (=4*3) full steps correspond to one revolution.

    Note: If there is a change of direction, a time of at least 35 µs must elapse before the new clock signal is applied.


The following bits in object 6041h (statusword) have a special function:

  • Bit 13 (Following Error): This bit is set in closed loop mode if the following error is greater than the set limits (6065h (Following Error Window) and 6066h (Following Error Time Out)).

Subtypes of the clock-direction mode

Clock-direction mode (TR mode)

To activate the mode, object 205Bh must be set to the value "0" (factory settings).

In this mode, the pulses must be preset via the clock input; the signal of the direction input specifies the direction of rotation here (see following graphic).

Right / left rotation mode (CW / CCW mode)

To activate the mode, object 205Bh must be set to the value "1".

In this mode, the input that is used decides the direction of rotation (see following graphic).

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