F07087 — Drive: Encoderless operation not possible for the selected pulse frequency

F07087 means that encoderless operation has been activated for the drive but cannot be used with the pulse frequency currently set. The manual names p1800 as the pulse frequency concerned: with the present setting, the activated encoderless operation is not possible, and the pulse frequency has to be increased before the drive can use it.

• The pulse frequency set in p1800 does not permit encoderless operation on this drive.
• Encoderless operation is activated because the changeover speed for encoderless operation (p1404) is less than the maximum motor speed (p0322).
• Encoderless operation is activated because a control type with encoderless operation has been selected (p1300).
• Encoderless operation is activated because encoder faults of the motor encoder result in a fault response with encoderless operation (p0491).

1. Increase the pulse frequency in p1800.
2. When selecting the new value, observe the sizing rule the manual gives: In encoderless operation, the pulse frequency must be at least as high as one quarter of the current controller clock cycle frequency (1/p0115[0]). p0115 is the sampling time for supplementary functions, so 1/p0115[0] is the current controller clock cycle frequency the pulse frequency must reach.

• Parameter: %1 — the drive enters the number of the parameter concerned in the message value.

• p1800 (Manipulated variable filter activation): the parameter in which the pulse frequency is set — increase the value here to clear the fault.
• p1404 (Encoderless operation changeover speed): check whether this changeover speed is set less than the maximum motor speed p0322, since that activates encoderless operation.
• p0322 (Maximum motor speed): the speed against which the changeover speed p1404 is compared in the activation condition.
• p1300 (Open-loop/closed-loop control operating mode): check whether the selected control type includes encoderless operation.
• p0491 (Motor encoder fault response ENCODER): check whether encoder faults of the motor encoder are set to result in a fault response with encoderless operation.
• p0115 (Sampling time for supplementary functions): 1/p0115[0] is the current controller clock cycle frequency that the pulse frequency must be sized against.

Correct the pulse frequency in p1800 as described above and then acknowledge the fault. Acknowledgement is specified as immediate, so the message can be cleared right away without powering the drive down. The drive does not execute an automatic fault response for this message; the parameterization itself has to be fixed before encoderless operation can be used.