Diagnostics For Changeover Contact Sensor Type - Siemens SIMATIC ET 200SP Manual

5.4

Diagnostics for changeover contact sensor type

Diagnostics for changeover contact sensor type
With the changeover error diagnostics, the switchover between two input channels is
checked. If there is a signal change in a changeover contact channel and there is no signal
change at the other contact changeover channel after the tolerated switchover time, the
diagnostics module returns a changeover error.
The tolerated switchover time between the two channels is set to the fixed value of 300 ms.
Changeover sensors are always assigned to two adjacent channels: The normally open
contact channel should be set in accordance with the sensor type to channel 0, 2, 4, 6, and
the respective corresponding normally closed contact channel 1, 3, 5, 7 deactivated.
Principle of changeover contact diagnostics
If the digital inputs of a channel group are configured as "changeover contacts", the module
for this channel group carries out diagnostics for the changeover contact sensor type.
If the validity check is negative, the following applies:
● The module identifies the value status of the normally open contact channel as "invalid"
● The module creates a diagnostics entry for the normally open contact channel and
● A diagnostics interrupt is triggered if changeover error diagnostics is enabled.
The digital input signal and the value status are only updated for the normally open contact
channel (channels 0, 2, 4, 6). The digital input signal is 0 and the value status is "invalid
(QI = "0") for the normally closed contact channel (channels 1, 3, 5, 7). This channel is only
used for a validity check of the sensor.
Please note the following special features for changeover contact diagnostics:
● If the normally open and normally closed contact signals are not plausible after 300 ms, a
● If there is already a fault (QI = 0, e.g. a wire break), the module will no longer perform
● There are different diagnostics options depending on the type of changeover contact
DI 8xNAMUR HF digital input module (6ES7131-6TF00-0CA0)
Manual, 02/2014, A5E03894478-01
(QI = "0"),
changeover error is output as diagnostics information.
diagnostics for changeover errors.
(Dependencies when configuring with GSD files (Page 32)). Depending on the sensor
type, a changeover error can have different causes.
– In the case of connected changeover contacts, a changeover error may also be the
result of a short-circuit (sensor is not defective; there is a short-circuit).
– In the case of unconnected changeover contacts, a changeover error may also be the
result of a wire break.
– If a wire break or short-circuit can be detected with the particular sensor type but its
diagnostics is not enabled, instead of the wire break or short-circuit diagnostics
information, the changeover error diagnostics information is displayed if this is
enabled.
5.4 Diagnostics for changeover contact sensor type
Interrupts/diagnostics alarms
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