Siemens Simatic M7-400 Reference Manual page 282

Analog Modules
Table 5-47 Diagnostics Messages of the Analog Input Modules, Causes of Errors and Remedial
Measures, continued
Diagnostics
Message
The module is defective
EPROM error
RAM error
ADC/DAC error
Hardware interrupt lost The module cannot send an
interrupt, since the previous
interrupt was not acknowledged;
configuration error possible
Configuring/parameter Illegal parameters transferred to
assignment error i t module
Short circuit to M A short circuit to the M potential has
occurred on the sensor supply of
two-wire transmitters
Wire break Resistance too high in the sensor
connection
Open circuit between module and
sensor
Channel not connected (open)
Reference channel
The reference junction connected at
error
channel 0 is faulty due to a wire
break, for example
The reference temperature value
transferred is not within the value
range
Underflow
Input value violates underrange,
error may be caused:
Wrong measuring range selected
With the measuring ranges 4 to
20 mA and 1 to 5 V, if necessary by
polarity reversal of sensor
connection
Overflow Input value overflows overrange
Run time calibration A wiring fault has occurred on a
error channel during the calibration cycle
5-66
Possible Error Cause
d l
S7-400, M7-400 Programmable Controllers Module Specifications
Remedy
Replace module
Change interrupt handling in the CPU
(change priority for interrupt OB; shorten
interrupt program)
Check measuring range module
Reassign module parameter
Eliminate short circuit
Use different type of sensor or
connection, e.g. use conductors with a
larger cross-sectional core area
Close circuit
Disable channel ("Measuring Type"
parameter)
Connect channel
Check terminals
Reparameterize the reference
temperature
Configure other measuring range
Check terminals
Configure other measuring range
Eliminate the wiring fault (fault remains
until the next calibration; in other words,
a maximum 6 minutes or until there is a
STOP-RUN transition of the CPU)
A5E00069467-07