Siemens Simatic S7-300 - Causes of Error and Troubleshooting at Analog Input Modules; Causes of Error and Troubleshooting at Analog Output Modules

Representation of the analog values of analog modules
5.8 Diagnostics functions of analog modules
S7-300 Automation System Module data
5-34 Manual, 08/2006, A5E00105505-04
5.8.3 Causes of error and troubleshooting at analog input modules
Overview of the causes of error and troubleshooting at analog input modules
Table 5-44 Diagnostics messages of analog input modules, causes of error and troubleshooting
Diagnostics message Possible cause of error To correct or avoid error
External load voltage
missing
Load voltage L+ of module missing Connect supply L+
Check the measuring range module Configuration /
programming error
Faulty parameters transferred to module
Program the module
Common-mode error Excess potential difference C
MV
between
inputs M- and the reference potential of
measuring circuit (M
ANA
)
Connect M- with M
ANA
Resistance of transducer circuit too high Use a different type of transducer, or modify the
wiring, for example, using a larger conductor
cross-section.
Open circuit between module and sensor Connect the cable
Disable the channel group ("measuring method"
parameter)
Wirebreak
Channel not connected (open)
Wire the channel
Input value below undershoot range;
possible cause of error:
wrong measuring range setting
set another measuring range
Underflow
at the measuring ranges 4 to 20 mA and 1
to 5 V, the sensor may be connected
revers polarity
Check the connections
Overflow Input value exceeds overshoot range set another measuring range
5.8.4 Causes of error and troubleshooting at analog output modules
Overview of the causes of error and troubleshooting routines at analog input modules
Table 5-45 Diagnostics messages of analog output modules, causes of error and troubleshooting
Diagnostics message Possible cause of error To correct or avoid error
External load voltage
missing
Load voltage L+ of module missing Connect supply L+
Configuration /
programming error
Faulty parameters transferred to
module
Program the module
Overload at output Eliminate overload Short-circuit to M
Short-circuit of output Q
V
to M
ANA
Eliminate the short-circuit
Actuator resistance too high Use a different type of actuator, or modify the wiring
using cables with a larger conductor cross-section
Wire-break between the module and
actuator
Connect the cable
Wirebreak
Channel not used (open) Disable channel group ("output type" parameter)