Setting the PWM state in the event of a watchdog trigger

The watchdog behavior can be configured for the following cases:

  1. in the event of a bus error via index 0x80n0:05 “Watchdog”
  2. in the event of PLC inactivity, via index 0x80n0:0C “Enable Output Cycle Counter Watchdog”
Setting the PWM state in the event of a watchdog trigger 1:

A loss of supply voltages is not a watchdog event

Please note that the loss of supply voltages via the E-bus, the power contacts, and the externally supplied voltage does not represent a watchdog event.

Setting the PWM state in the event of a watchdog trigger 2:

Notes on the switching behavior of the outputs

  • With an inductive load:
    The switching behavior of the output with inductive loads deviates from the specified switching times due to the inductance of the selected load.
  • In tristate mode:
    Internal circuit causes a leakage current in tristate mode, which pulls the potential toward ground. This corresponds to a pull-down resistance in the range of typically < 4 kOhm.
  • When switching via a PLC variable:
    If the output is switched via a PLC variable, the delays caused by the PLC cycle time must also be taken into account in addition to the TON/TOFF.

CAUTION

Watchdog settings

Changes to the watchdog settings can lead to unwanted system behavior or damage to devices.

  • Observe the information in the chapter “Notes on watchdog settings” in the EtherCAT system documentation before making any changes to the watchdog settings!
Further Information