Siemens Simatic S7-1500 Manual page 55

Diagnostic alarm
Sensor signal flutters
Frequency too high
Undertemperature
Input shorted to P
Supply voltage too high
Supply voltage too low
Supply voltage outside the nominal range
If the supply voltage L+ is outside the specified value range, the ERROR LED flashes and
the module is passivated.
When the voltage is then recovered (level must remain within the specified value for at least
1 minute, see Technical specifications (Page 57)), the ERROR LED stops flashing. The
module remains passivated and waits for user acknowledgment.
Behavior in case of cross circuit/short-circuit to the sensor supply
When internal sensor supply is configured and short-circuit test is deactivated, short-circuits
to ground at the sensor supplies are detected. Channels for which the relevant sensor supply
is configured will be passivated.
When internal sensor supply is configured and short-circuit test is enabled, short-circuits to
ground and potential at the sensor supply are detected. Channels for which the relevant
sensor supply is configured will be passivated.
Digital input module F-DI 16x24VDC (6ES7526-1BH00-0AB0)
Manual, 01/2016, A5E03858068-AA
Fault
code
784 Too many signal changes have occurred
D
within the time configured with the "Monitor-
ing window" parameter.
The "Monitoring window" parameter
•
setting is too high.
The "Number of signal changes" pa-
•
rameter setting is too low.
A momentary interruption/short-circuit of
•
the sensor cable (loose contact) is pre-
sent.
Impermissibly high electromagnetic
•
interference is present.
The sensor/switch is bouncing.
•
The sensor is defective.
•
785 The switching frequency of the encoder is
D
too high.
786 The minimum permissible temperature limit
D
has been violated.
796 The input signal is short-circuited to L+.
D
801 The supply voltage is too high.
D
802 The supply voltage is too low.
D
Meaning
Interrupts/diagnostic messages
6.3 Diagnostic alarms
Remedy
Check the "Monitoring window"
•
parameter.
Check the "Number of signal
•
changes" parameter.
Check the process wiring.
•
Eliminate/reduce the electromag-
•
netic interference.
Replace the sensor.
•
Reduce the switching frequency of
the sensor.
Operate the F-module within the
specified temperature range (see
Technical specifications (Page 57))
Eliminate the short-circuit.
Check the supply voltage.
Check the supply voltage.
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