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Connect Devices
WAGO-I/O-SYSTEM 750
750-666/000-003 4FDI/2FDO 24V/10A PROFIsafe V2 iPar
Manual
Version 1.2.0, valid from HW/SW Version 01/01
6.3.3.8.1 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 PROFIsafe I/O
module, but on the external diode recovery circuit.
The external diode recovery circuit must be designed for the resulting heat loss.
When shutting down an inductive load, the magnetic energy stored in the
inductive load must be dissipated. This magnetic energy converted by a diode
recovery circuit into heat. You can convert the magnetic energy into heat with the
PROFIsafe I/O module or with a suitable external diode recovery circuit.
As the magnetic energy depletes, a negative voltage occurs on the inductance. The
diode recovery circuit integrated in the PROFIsafe I/O module has a different
limitation of negative voltage depending on the connection variant and the value
of the field voltage. The external diode recovery circuit must have a less voltage
than that of the PROFIsafe I/O module.
Figure 42: Connection variant with 1 diode recovery circuit
If you connect the inductive load in the output configuration H-Side/L-Side 1
between connections O1B and O2A, you have to make sure when selecting the
external diode recovery circuit that the negative voltage is limited to an absolute
value less than U
L
= -95 V. Otherwise, the magnetic energy is converted by the
PROFIsafe I/O module into heat.
