Siemens Simatic S7-1500 Manual page 54

Interrupts/diagnostic messages
6.3 Diagnostic alarms
Diagnostic alarm
Input signal not recorded
unique
Internal sensor supply short-
circuit to P
Overload or internal sensor
supply short-circuit to ground
Channel failure acknowledg-
ment
F-address memory not ac-
cessible
54
Fault
code
773 An error occurred during the plausibility
D
check of the input signal between the pro-
cessors.
Possible causes:
The input signal is faulty, e.g., as a
•
result of impermissibly high electro-
magnetic interference.
A high-frequency input signal is present,
•
e.g., due to mutual interference of sen-
sors or the signal being above the sam-
pling frequency of the input signal.
A momentary interruption/short-circuit of
•
the sensor cable (loose contact) is pre-
sent.
The sensor/switch is bouncing.
•
774 Possible causes:
D
There is a short-circuit of the internal
•
sensor supply with L+.
There is a short-circuit of two sensor
•
supplies.
The capacitance of the connected sen-
•
sor for the configured test time is too
high.
The sensor is defective.
•
775 Possible causes:
D
The internal sensor supply is short-
•
circuited to ground.
Impermissibly high electromagnetic
•
interference is present.
779 A channel fault was detected. Confirmation
D
is required to enable the channel.
781 The F-source address and F-destination
D
address stored in the coding element can-
not be accessed.
Meaning
Digital input module F-DI 16x24VDC (6ES7526-1BH00-0AB0)
Remedy
Use shielded cables to reduce
•
the EMC effects.
Reduce the input frequency.
•
Check the wiring of the sensor.
•
Eliminate the short-circuit in the
•
process wiring.
Check the configured test time
•
and the process wiring.
Replace the sensor.
•
Eliminate the overload.
•
Eliminate the short-circuit in the
•
process wiring.
Check the "Sensor supply" pa-
•
rameter.
Eliminate/reduce the electromag-
•
netic interference.
Confirm the channel fault.
Verify that the coding element is
present or replace the coding ele-
ment.
Manual, 01/2016, A5E03858068-AA