Switching Inductive Loads; 7.3.3.2.1 Selecting An External Diode Recovery Circuit - WAGO -I/O-SYSTEM 750 Manual

72 Connect Devices
7.3.3.2

Switching Inductive Loads

Defect by thermal overheating if the switching frequency is too high!
If the inductivity and load current you have selected is too high for the selected
switching frequency, it can lead to thermal destruction of the digital power output.
Destruction of the digital power output can cause the safety function to fail.
You can operate inductive loads on the digital power outputs of the F I/O module
by using the internal recovery circuit. Depending on the size of the inductance of
the load and the value of the load current, the switching frequency specified in
the technical data may be maximum 0.1 Hz higher.
The following figure represents the maximum permissible inductance of the load
based on the load current and switching frequency.
Figure 2: Switching Frequency Based on the Inductance and Load Current

7.3.3.2.1 Selecting an External Diode Recovery Circuit

Pay attention to heat loss from the external diode recovery circuit!
If you use a suitable external diode recovery circuit, then the magnetic energy
when shutting down the inductive load is not converted in the F I/O module, but
on the external diode recovery circuit.
The external diode recovery circuit must be designed for the resulting heat loss.
Manual
Version 1.4.2, valid from HW/SW Version 01/02
750-667/000-003 4FDI/4FDO 24V/2A PROFIsafe V2 iPar
WAGO-I/O-SYSTEM 750