2 Solution
2.1 Overview of the general solution
Monitoring of 24 V load circuits
Entry-ID: 61450284, V1.1, 05/2014
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The following table represents a list of the used software components.
Table 2-2
Block in the
S7-CPU
Function
Comment
PSE_DIAG
(FB50)
The block:
evaluates the signal of
the state output (S)
indicates the state of
outputs OUT 1 to OUT 4
at its output
Universal block from the
SITOP_Library_V12_S7-300_S7-400
library; not modified by the user
Messages
(FB10)
The block creates PLC
alarms with ALARM_D, which
are indicated at the SIMATIC
Panel.
The SIMATIC Panel displays
messages if the load circuits
connected at outputs OUT 1
to OUT 4 fail or are switched
off.
Individual function block which can be
modified and adjusted by the user
Advantages
The application on hand offers you the following advantages:
Detecting overload or short-circuit in individual 24 V load circuits reliably –
even for long and thin lines or creeping short-circuits – and switches the 24 V
load circuits to zero current.
Avoiding plant down times by maintaining the 24 V supply of the remaining
consumers.
Sequential switching of the individual channels unloads the power supply.
Reducing down-times by fast and channel-specific error localization of the
faulty 24 V load circuit via direct integration into the S7 diagnosis (via the
PSE_DIAG (FB50) function block).
Simple and cost-efficient connection to a PLC. Only one single digital input per
PSE200U module is required.
Topics not covered by this application
This application does not include a description of
programming and configuration in STEP 7 V12
programming and configuration in WinCC V12
Basic knowledge of these topics is assumed.
