Behaviour of MCTRL-M-ADD and MCTRL-N/M-SWT in case of U/f characteristic control

Which products are affected?
9300 vector 0.37…90 kW SW ≤ V6.3

What happens?
Occurrence of speed fluctuations and peak currents

When does the problem occur?
By setting the digital MCTRL-N/M-SWT signal to HIGH level, the analog MCTRL-NSET2 signal (speed setpoint) is influenced erroneously. As a result, peak currents and speed fluctuations are sporadically activated. According to the documentation the MCTRL-N/M-SWT signal is without influence in case of U/f characteristic control (C0006 = 5).

Possible diagnostics?
Check the connection of MCTRL-N/M-SWT.

Short-term measures/recommendations?
Do not connect any signal to the MCTRL-N/M-SWT digital input if the drive is to be used in U/f characteristic control mode. As a result, the input is automatically on LOW level.

Evaluation:
A torque control is principally not possible in U/f characteristic control mode (C0006 = 5). Therefore, a connection to the digital MCTRL-N/M-SWT input does not make sense in U/f characteristic control mode and should be removed if necessary.

URL for linking this AKB article: https://www.lenze.com/en-de/go/akb/200504944/1/
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