Monitoring of the 24V power supply (terminal X5/24E)

Question:

Under what conditions does the "External Supply Voltage Critical" (0x5112) monitoring trigger on the i950/i750?

Answer:

If the control card supply voltage of the servo inverter remains below U_monit=21V for longer than t=15ms, the warning 0x5112'External supply voltage critical' is logged.
This may indicate that the 24V network is unstable or incorrectly sized.

During a 'normal shutdown', entry 0x5112 is generally not logged, as the voltage drops below the threshold of U=18V for the power-down sequence in less than15 ms.
Depending on which other devices are powered by the same 24V power supply, the 24V voltage may also decay more slowly, e.g., if capacitors in the other devices support the voltage. In such cases, 0x5112 entries may still be observed in the logbook.

Note:
For some servo inverters, e.g., the i950 up to 4 kW, the control card must always be powered externally via terminal X5/24E. Larger inverter sizes have an internal switching power supply that derives the power for the electronics from the DC link voltage of the power section.

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