Connection Examples For Digital Power Outputs; Switching Grounded Loads - WAGO -I/O-SYSTEM 750 Manual

WAGO-I/O-SYSTEM 750
750-667/000-003 4FDI/4FDO 24V/2A PROFIsafe V2 iPar
A suitable module must be used in the safety application of the safe PLC to
analyze the input bits.
Note
Use application notes from WAGO!
An overview for using F I/O module in combination with a safe PLC is
summarized in an application note. This application note is available on the
Internet at
Application Notes..."
7.3.3

Connection Examples for Digital Power Outputs

On the F I/O module, the following loads can be operated on the digital power
outputs:
• Resistive loads
• Inductive loads after DC13 acc. EN 60947-5-1
7.3.3.1

Switching Grounded Loads

Figure 1: Grounded Load Connection
When switching loads that are connected between the digital power output and
the Ox- (O1- ... O4-) ground connection (e.g., to improve EMC properties) from
the F I/O module and when the attached power supply is connected between the
common (ground) connection of the field supply voltage and the ground
connection, then this type of circuit leads to detection of a short circuit and to the
"Short circuit to GND" diagnostic message.
This happens because the connection bridges the digital power output Ox-. As a
remedy, the connection between the ground connection and the common
(ground) connection of the field supply voltage must have a total resistance RE
(see figure) of at least 32 kΩ.
You can accomplish this by placing an additional resistor between the common
(ground) connection of the field supply voltage and the ground connection.
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