Why Have a Fallback Mode?
The physical outputs from TSX CTY 2A/4A modules can directly control certain parts of the process. It is therefore necessary for the safety of the operation to have a fallback mode in the event of a fault in the outputs themselves, the module or the application.
The state of Q0 and Q1 physical outputs is forced to 0 when one of the following faults occurs:
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tripped output (short-circuit or voltage surge),
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module failure,
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self-testing in progress,
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auxiliary input/output fault,
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counting input fault,
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fault in the counting application,
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application fault,
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stop in communication with the PLC: special fault for which the fallback mode can also be configured following the table below.
All these faults are indicated by the software. The relevant language objects are described in the
implicit objects section.
Communication Stop - Special Case
If communication with the PLC stops:
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If the fallback mode is configured to
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Then outputs are
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Reset,
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forced to 0,
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maintain
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maintained in the state they were before the fault appeared.
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In the event of a voltage surge or short-circuit of an output, a trip is indicated:
In addition, a current limit of 625 mA is put in place.
