Outputs fallback mode for TSX CTY2C modules in the event of a fault
(Original Document)
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Why have a fallback mode?
The physical outputs from TSX CTY2C 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.
For a TSX CTY2C modules, the fallback modes vary according to:
Fallback conditions in manual mode
In the event of one of the following faults :
Q0 to Q3 outputs in manual mode :
  • module failure,
  • self-testing in progress,
  • counting application fault(invalid software configuration or channel reconfiguration),
  • auxiliary inputs/outputs fault,
  • auxiliary input power supply fault,
  • tripping of any output (short circuit or voltage surge),
are reset to zero.
  • counting input fault
  • counting application fault (adjustment fault),
  • fault in the encoder power supply or sensor,
  • encoder line break or short-circuit,
  • SSI series frame fault,
  • specific absolute encoder fault,
  • measurement overrun or overspeed
are not reset to zero.
All these faults are indicated by the software via language objects. To find out the associated language objects, see CH_FLT word for explicit language objects
Fallback conditions in automatic mode
When outputs are in automatic mode, they are reset to zero whatever the fault. In this way the module ensures the safety of the operation, even if the fault is masked.
These faults are also indicated by the software.
Communication fault – special case
In the event of PLC communication stopping, independently of manual or automatic output mode:
If the fallback mode is configured to
Then outputs are
Reset,
forced to 0,
maintain
maintained in the state they were before the fault appeared.
Indicating a trip
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.