7

System Status (%S) References

System status references are pre-defined locations and nicknames. They can be included in the application program to check for fault-related conditions. For example, status references can be used to:

HDetect forces and overrides.

HMonitor the fault tables.

For a complete listing of %S references, see the Series 90-70 PLC Reference Manual.

Monitoring Forces and Overrides

The GMR software cannot detect point forces and overrides, and their use is not recommended and may affect the results of autotesting. Forcesand/oroverrides can also affect GMR voting of inputs and outputs. Therefore, if the system will include the use of forcesand/oroverrides, it is important to include application program logic to detect them.

These system status references detect forces and overrides in an individual PLC:

%S0011

OVR_PRE

when set, indicates an override in %I, %Q,

 

 

%M, or %G memory.

%S0012

FRC_PRE

when set, indicates a force on a Genius point.

Monitoring the Fault Tables

These system status references are associated with the fault tables in an individual PLC:

%S0009

SY_FULL

when set, indicates that the PLC Fault Table is

 

 

full.

%S0010

IO_FULL

when set, indicates that the I/O Fault Table is

 

 

full.

%SC0010

SY_FLT

when set, indicates that an entry has been

 

 

placed in the PLC Fault Table.

%SC0011

IO_FLT

when set, indicates that an entry has been

 

 

placed in the I/O Fault Table.

%SC0012

SY_PRES

when set, indicates that there is presently at

 

 

least one entry in the PLC Fault Table.

%SC0013

IO_PRES

when set, indicates that there is presently at

 

 

least one entry in the I/O Fault Table.

7-10

GeniustModular Redundancy Flexible Triple Modular Redundant (TMR) System

GFK-0787B

 

User's Manual ± March 1995

 

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Image 153
GE GFK-0787B user manual System Status %S References, Monitoring Forces and Overrides, Monitoring the Fault Tables