Safety Considerations Guide for Trident v2 Systems - TUV ...

84 Appendix C Safety-Critical Function Blocks
Instructions for Use
To initialize, invoke once with RESET := TRUE.
To complete initialization, invoke again with these input settings:
• RESET := FALSE
• CI := TRUE
• APP := DE_ENERGIZED
• RELAY_OK := false
To get the status of a safety-critical I/O module:
• For each module, invoke specifying the input values:
• IOP
• SLOT
• APP
• RELAY_OK
For example, if IOP 1 SLOT 1 is a critical DO module with a relay, and SCIO is the
function block instance name:
SCIO( IOP:=1, SLOT:=1, APP:=RELAY,RELAY_OK:=RELAY1_OK );
• Read the output values:
• CO
• TMR
• GE_DUAL
• GE_SINGLE
Example
For shutdown examples, see the sample project located at My Documents\Triconex\TriStation
1131 4.x\Projects\TdTUV.pt2
Runtime Errors
Condition Return Value Error Flags
If ERROR_NUM is non-zero Reset all BOOL outputs to false BADPARAM, ERROR
Upon detection of a runtime error condition, the function block returns the indicated values and
sets the error flags to true. For more information about error flags and runtime errors, see the
TriStation 1131 Libraries Reference.
Application Notes
• Can be used in Safety or Control applications.
Safety Considerations Guide for Trident v2 Systems