Siemens SIMATIC User Manual

Principles of analog modules
5.8 Diagnostics of analog modules
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
297
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- 46 Diagnostics messages of analog input modules, causes of error and troubleshooting
Diagnostics message
Possible cause of error
To correct or avoid errors
External load voltage miss-
ing
Load voltage L+ of module missing Connect supply L+
Configuration / program-
ming error
Faulty parameters transferred to module Check the measuring range module
Program the module
Common-mode error Potential difference C
MV
between inputs M-
and the reference potential of measuring
circuit (M
ANA
out of limits)
Connect M- with M
ANA
Wirebreak Resistance of transducer circuit too high Use a different type of sensor, or modify the
wiring, for example, using a larger conductor
cross-section.
Open circuit between module and sensor
Connect the cable
Channel not connected (open) Disable the channel group ("measuring method"
parameter)
Wire the channel
Underflow Input value below undershoot range; pos-
sible cause of error:
wrong measuring range setting
program a different measuring range
polarity reversal of the sensor wiring in the
measuring ranges 4 to 20 mA and 1 to 5 V
Check the connections
Overflow
Input value exceeds overshoot range
program a different 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 output modules
Table 5- 47 Diagnostics messages of analog output modules, causes of error and troubleshooting
Diagnostics message
Possible cause of error
To correct or avoid errors
External load voltage miss-
ing
Load voltage L+ of module missing Connect supply L+
Configuration / program-
ming error
Faulty parameters transferred to mod-
ule
Assign new module parameters
Short-circuit to M
Overload at output
Eliminate overload
Short-circuit at output Q
V
to M
ANA
Eliminate the short-circuit
Wirebreak Actuator impedance 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
Channel not used (open)
Disable the channel group ("output type" parameter)

Siemens SIMATIC Specifications

General

Product type designation	SIMATIC
CPU	Varies by model
Memory	Varies by model
Input/Output	Varies by model
Communication	Varies by model
Programming Language	STEP 7
Operating Temperature	0°C to 60°C (varies by model)
Protection Class	IP20
Category	Programmable Logic Controller (PLC)