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portion of the bus between the BSM and the blocks) result in loss of the blocks downstream from the failure on that bus stub.
Bus failures in single bus networks result in loss of the blocks downstream from the bus failure.
When using the GDB control strategy, the user is required to transfer all redundant Genius outputs to the backup unit so that both units drive the same output values.
%S References for CPU Redundancy
%S33 through %S39 and %SB18 reflect the status of the Redundancy units. The table below describes these %S references, and shows their expected states in the Primary and Secondary Units, assuming Primary is active and Secondary is backup.
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%S Bit | Definition | Nickname | Description |
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Primary | Secondary | |||||
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%S33 | Primary Unit | PRI_UNT | Set if the local unit is configured as the primary unit: | ON | OFF | |
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| otherwise; it is cleared. For any given local unit, if |
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| PRI_UNT is set, then SEC_UNT cannot be set. |
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%S34 | Secondary Unit | SEC_UNT | Set if the local unit is configured as the secondary unit: | OFF | ON | |
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| otherwise; it is cleared. For any given local unit, if |
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| SEC_UNT is set, then PRI_UNT cannot be set. |
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%S35 | Local System | LOC_RDY | Set if local unit is ready to become the active unit; | ON | ON | |
| Ready |
| otherwise it is cleared. |
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%S36 | Local System | LOC_ACT | Set if local unit is currently the active unit; otherwise it is | ON | OFF | |
| Active |
| cleared. For any given local unit, if LOC_ACT is set, then | OFF (1) | ON (1) | |
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| REM_ACT cannot be set. | |||
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%S37 | Remote System | REM_RDY | Set if remote unit is ready to become the active unit; | ON | ON | |
| Ready |
| otherwise it is cleared. |
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%S38 | Remote System | REM_ACT | Set if remote unit is currently the active unit; otherwise it is | OFF | ON | |
| Active |
| cleared. For any given local unit, if REM_ACT is set, then | ON (1) | OFF (1) | |
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| LOC_ACT cannot be set. | |||
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%S39 | Logic Equal | LOGICEQ | Set if the logic program for both units in the redundant | ON | ON | |
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| (LOGIC=) | system is the same; otherwise the bit is cleared. |
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%SB18 | Redundant | RDN_MSG | Set if a redundant informational message was logged. It can be cleared in reference tables, | |||
| Informational |
| logic, or by clearing the fault tables. |
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| Message, Fault |
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| Logged |
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(1) Condition if secondary is active unit.
%S references can be read from the application program, but cannot be altered or overridden. These references are always OFF when no configuration has been stored. Once you have completed configuration of the Redundancy system and STORED the configuration, the state of these %S references is set and is maintained in STOP or RUN mode.
References %S35, %S36, %S37, and %S38 correspond to LEDs on the Redundancy Communications Module. External indicators can also be used to monitor the status of %S35 through %S38 (Local Ready/Active, Remote Ready/Active) through the application program logic.
OVR_PRE %S Reference Not Available
The OVR_PRE %S reference which indicates whether one or more overrides is active is not supported by the Redundancy CPU and should not be used.
Chapter 4 Normal Operation |
