Function description
Operating Manual PSSu E F 4DI(-T)(-R),
21310-EN-08
12
4
Function description
4.1
Block diagram
Module Bus
Periphery
Supply
+ 24 V DC
Module
Supply
+ 5 V DC
Data
(FS)
Input
Input
Input
Input
11
12
21
22
14
13
24
23
4.2
Functions
Module supply
}
The module supply provides the module with voltage.
Periphery supply
}
The module switches the periphery supply from the module bus to the base module ter-
minals.
}
The periphery supply is used to supply or provide test pulses to the input devices.
Inputs
}
The input status is signalled to the head module via the module bus.
}
Test pulses can be used to check the inputs for shorts across contacts and correct
functionality.
}
The inputs have input filters.
Test pulse outputs
}
2 test pulse outputs that use different test pulses (test pulse 0, test pulse 1)
}
Short circuit-proof
}
Current limitation
}
Test pulses can be switched on or off.
}
Test pulses are switched on in the default setting.
}
When test pulses are switched off, the periphery supply is constantly available at the
outputs.
Detection of shorts across contacts
}
The test pulses are used to detect shorts between inputs. Shorts between inputs are
detected when
– the test pulses are different (test pulse 0, test pulse 1) or when
