GSV/SSV Instructions in a Safety Application
For standard tasks, you can use the GSV instruction to get values for the available attributes. When using the SSV instruction, the software displays only the attributes that you can set.
For the safety task, the GSV and SSV instructions are more restricted. The SSV instructions in safety and standard tasks cannot set bit 0 (major fault on error) in the mode attribute of a safety I/O device.
ATTENTION:
Use the SSV instruction carefully. Making changes to objects can cause unexpected controller operation or injury to personnel.
FaultRecord Attributes
Create a user-defined structure to simplify access to the MajorFaultRecord and SafetyTaskFaultRecord attributes.
Name | Data Type | Style | Description |
|---|---|---|---|
TimeLow | DINT | Decimal | Lower 32 bits of the fault time stamp value |
TimeHigh | DINT | Decimal | Upper 32 bits of the fault time stamp value |
Type | INT | Decimal | Fault type (program, I/O, or other) |
Code | INT | Decimal | Unique code for this fault (dependent on fault type) |
Info | DINT[8] | Hexadecimal | Fault-specific information (dependent on fault type and code) |
Fault Information
The SafetyStatus and SafetyTaskFaultRecord attributes can capture information about nonrecoverable faults. Use a GSV instruction in the controller fault handler to capture and store fault information. The GSV instruction can be used in a standard task with a controller fault handler routine that clears the fault and lets the standard tasks continue executing.
For more information on using the GSV and SSV instructions in safety applications, refer to the Input/Output Instructions chapter of the Logix 5000 Controllers General Instructions Reference Manual, publication 1756-RM003.
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