II - DCE FEL ČVUT v Praze

Faults and
corrective
measures
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Table 3-27 provides a list of possible causes and corresponding corrective
measures for individual diagnostic messages.
Bear in mind that, in order to detect faults which are indicated by means of
configurable diagnostic messages, the module must also be parameterized
accordingly.
Table 3-27 Diagnostic messages of analog output module SM 332; AO 4 x 0/4...20 mA and their possible causes
and corrective measures
Wire break
Diagnostic message Possible fault cause Corrective measures
Break in line between module and
actuator
Incorrect parameters in module Module supplied with invalid
parameters
Connect line
Voltage at load resistor > 12V Lower load resistance to 500
Channel not connected (open) Deactivate channel (”Measurement
mode parameter)
Check parameterization of module
and re-load valid parameters
Module not parameterized Module not supplied with parameters Include module in parameterization
No external auxiliary voltage No module supply voltage L+ Provide L+ supply
No internal auxiliary voltage No module supply voltage L+ Provide L+ supply
Module-internal fuse defective Replace module
Fuse blown Module-internal fuse defective Replace module
Time watchdog tripped In part, high electromagnetic
interference
EPROM error
CPU error
RAM error
Reading out
diagnostic
messages
Eliminate interference sources
Module defective Replace module
In part, high electromagnetic
interference
Module defective Replace module
SIMATIC S7 Ex Analog Modules
Eliminate interference sources and
switch CPU supply voltage OFF/ON
You can read out the detailed diagnostic messages in STEP 7 after setting
diagnostics for the analog modules (refer to /231/).
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