F07421 — Drive: Speed filter natural frequency > Shannon frequency

F07421 is raised when the natural frequency parameterized for one of the drive's speed filters lies above the Shannon frequency. The drive calculates the Shannon frequency as 0.5 / p0115[1], where p0115[1] is the sampling time for supplementary functions. The check covers the numerator and denominator natural frequencies of speed setpoint filter 1 (p1417, p1419), of speed setpoint filter 2 (p1423, p1425) and of the speed actual value filter (p1447, p1449). The fault value in r0949 shows, interpreted binary, which filter is affected and in which data set.

• One of the filter natural frequencies is greater than the Shannon frequency, which the drive calculates as 0.5 / p0115[1].
• The frequency that exceeds the limit was parameterized in speed setpoint filter 1 (p1417, p1419), in speed setpoint filter 2 (p1423, p1425) or in the speed actual value filter (p1447, p1449).

1. Read the fault value r0949 in binary: Bit 0 points to speed setpoint filter 1 (p1417, p1419), Bit 1 to speed setpoint filter 2 (p1423, p1425) and Bit 4 to the speed actual value filter (p1447, p1449); Bits 8 … 15 give the data set number (starting from zero) in which the impermissible frequency was parameterized.
2. Reduce the numerator or denominator natural frequency of the filter involved — p1419 or p1417 (filter 1), p1425 or p1423 (filter 2), p1449 or p1447 (actual value filter) — until it lies below the Shannon frequency 0.5 / p0115[1].
3. Alternatively, reduce the sampling time p0115[1]; the Shannon frequency 0.5 / p0115[1] then rises above the filter natural frequency.
4. Alternatively, switch off the filter involved: p1414 switches off the speed setpoint filters, p1413 the speed actual value filter.

• The drive stores the fault value in r0949; interpret it binary.
• Bit 0: Filter 1 (p1417, p1419)
• Bit 1: Filter 2 (p1423, p1425)
• Bit 4: Actual value filter (p1447, p1449)
• Bit 8 … 15: Data set number (starting from zero)

• r0949 — fault value: read it in binary to see which filter (Bit 0, Bit 1, Bit 4) and which data set (Bits 8 … 15) is affected.
• p0115[1] — sampling time for supplementary functions: it determines the Shannon frequency 0.5 / p0115[1]; reducing it is one of the remedies.
• p1417 — denominator natural frequency of speed setpoint filter 1: reduce it when Bit 0 is set.
• p1419 — numerator natural frequency of speed setpoint filter 1: reduce it when Bit 0 is set.
• p1423 — denominator natural frequency of speed setpoint filter 2: reduce it when Bit 1 is set.
• p1425 — numerator natural frequency of speed setpoint filter 2: reduce it when Bit 1 is set.
• p1447 — denominator natural frequency of the speed actual value filter: reduce it when Bit 4 is set.
• p1449 — numerator natural frequency of the speed actual value filter: reduce it when Bit 4 is set.
• p1413 — velocity actual value filter activation: use it to switch off the actual value filter as an alternative to reducing its natural frequency.
• p1414 — velocity setpoint filter activation: use it to switch off a setpoint filter as an alternative to reducing its natural frequency.

Correct the parameterization first — bring the affected natural frequency below the Shannon frequency 0.5 / p0115[1] or switch the filter involved off — and then acknowledge the fault. The configured reaction is no automatic stop, so the drive does not trip when F07421 is raised; OFF1, OFF2 or OFF3 can be selected as the reaction instead.