Reflex function block: Type 1 command-check
(Original Document)
About us
Role
This function is used to command an action and to check whether it has been carried out after time period ti
Structure
The table below shows the block's different interfaces.
Name
Meaning
Illustration
Cde
Command input.
Ctrl
Control input.
Acq
Acknowledgement of fault.
x
Block's physical output.
x Aux
Block's internal auxiliary output.
Operation
This table describes the different operating phases of the type 1 command-check function.
Phase
Description
1
On the rising edge of input Cde:
  • time-out ti is launched,
  • input x changes to 1.
2
When time-out ti is over:
  • if the Ctrl signal changes to status 1 during the time-out interval, the x Aux output stays at 0 (normal situation),
  • if the Ctrl signal is not received, the x Aux output changes to 1 (type A error signal).
  • if the Ctrl signal falls back while the Cde input is at 1, the x Aux output changes to 1 (type B error signal).
A rising edge on the Acq input with the Ctrl input at 1 causes the x Aux to be set to 0.
3
On the falling edge of the Cde input, the x and x Aux outputs change to 0.
Illustration
The illustration below shows the trend diagram of the type 1 command-check function block.