Short circuit monitoring

The following parameters are available in group 8809 "Output stage monitoring – Power supply for configuring short circuit monitoring".

These can normally be left at the default values.

  • 8809.100 "Short circuit monitoring: voltage limit (A‑side)"
  • 8809.101 "Short circuit monitoring: voltage limit (B‑side)"
  • 8809.102 "Short circuit monitoring: activate (A‑side)"
  • 8809.103 "Short circuit monitoring: activate (B‑side)"

Furthermore, short circuit monitoring requires information about the connected capacitances to detect a short circuit correctly. This information relates to the parameters of other groups. Their values must be set in accordance with the application:

  • 8811 "Configuration – power supply"
    • 8811.11 "Output stage capacitance (A‑side)". This value is obtained from the configuration data of the device.
    • 8811.12 "Output stage capacitance (B‑side)". This value is obtained from the configuration data of the device.
    • 8811.13 "Capacitance application fixed (A‑side)".
    • 8811.14 "Capacitance application fixed (B‑side)".
  • 8817 "Configuration data – storage unit".
    • 8817.6 "Capacitance".
  • 8818 "Charge management".
    • 8818.52 "Output stage end".
    • If a short circuit is detected, the device signals fault E7.8 A‑side or B‑side short circuit.

Short circuit monitoring during charging

Monitoring can only detect the short circuit if the device is currently feeding current into this short circuit.

This is a plausibility check between the energy applied to the monitored side, the capacitance of this side, and the resulting voltage rise.

Monitoring is performed up to the voltage limit set by parameter 8809.100 or 8809.101. This means that the measurement lasts until the voltage must theoretically have risen above this limit. In order to be able to work reliably, the voltage must therefore be selected in such a way that up to this voltage no consumers start up.

The lower the voltage limit, the shorter the time until a short circuit is signaled. And consequently also the time during which the current flows into the short circuit. The higher the capacitance or the lower the applied current, the slower will the voltage rise and consequently also the time until a fault is detected.

Short circuit monitoring during operation

Fast transient voltage dips are monitored in this case. A short circuit is detected if an implausible voltage drop is detected for the specified capacitance.