A01902 — PB/PN: clock cycle synchronous operation parameterization not permissible

A01902 is issued when the parameterization for isochronous (clock cycle synchronous) operation over PROFIBUS (PB) or PROFINET (PN) is not permissible. The drive writes an alarm value into r2124 that identifies exactly which of the timing conditions for isochronous operation has been violated.

• The configured isochronous operation is impermissible — the bus cycle time, the sensing and setpoint instants and the controller sampling times do not fit together as the drive requires. Which condition fails is shown by the alarm value in r2124.

1. Read the alarm value in r2124 (interpret it as a decimal number) and find the violated condition in the list below.
2. Adapt the bus parameterization — the bus cycle time Tdp, the instant of the actual value sensing Ti and the instant of the setpoint acceptance To.
3. Alternatively, adapt the sampling time of the current controller or of the speed controller.
4. If the alarm value is 10, reduce the data exchange time Tdx by using fewer bus participants or shorter telegrams.

The alarm value is stored in r2124 and, per the manual, is interpreted as a decimal number. Each value names one condition that makes the isochronous parameterization impermissible:

• 0: Bus cycle time Tdp < 0.5 ms.
• 1: Bus cycle time Tdp > 32 ms.
• 2: Bus cycle time Tdp is not an integer multiple of the current controller sampling time.
• 3: Instant of the actual value sensing Ti > Bus cycle time Tdp or Ti = 0.
• 4: Instant of the actual value sensing Ti is not an integer multiple of the current controller sampling time.
• 5: Instant of the setpoint acceptance To >= Bus cycle time Tdp or To = 0.
• 6: Instant of the setpoint acceptance To is not an integer multiple of the current controller sampling time.
• 7: Master application cycle time Tmapc is not an integer multiple of the speed controller sampling time.
• 8: Bus reserve bus cycle time Tdp - data exchange time Tdx less than two current controller sampling times.
• 10: Instant of the setpoint acceptance To <= data exchange time Tdx + current controller sampling time
• 11: Master application cycle time Tmapc > 14 x Tdp or Tmapc = 0.
• 12: PLL tolerance window Tpll_w > Tpll_w_max.
• 13: Bus cycle time Tdp is not a multiple of all basic clock cycles p0110[x].
• 16: For COMM BOARD, the instant in time for the actual value sensing Ti is less than two current controller sampling times.

• r2124 — alarm value: read it as a decimal number to find out which of the timing conditions listed above was violated.

This alarm requires no acknowledgement, and the drive takes no action in response to it. Once the isochronous bus parameterization has been corrected as described above, the condition for the alarm is removed.