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Operation
Operational Modes and Controls
Table 15 Controller mode switch summary
Controller Mode Manual
Switch setting
RUN
OFFLINE
PROGRAM
Mode Control
through the Configuration Port or Operator Interface
Unrestricted mode changes.
The mode selected via the Configuration port or operator interface overrides the controller manual mode switch position.
Can override OFFLINE mode to set controller to PROGRAM mode.
No mode changes can be made.
Setting mode switch to PROGRAM and then to RUN
Setting the controller mode switch to PROGRAM and then to RUN forces the controller to perform a cold start and other actions depending upon the condition of the database RAM. When the mode switch is changed from PROGRAM to RUN, the controller verifies that a valid database configuration is present in RAM before starting control loops.
So that,
If . . . (Condition of RAM)
A valid database configuration is present in RAM,
Database configuration in RAM is found to be bad, but the configuration in flash PROM is good,
Then . . . (Controller Action)
Configuration is written to flash PROM. (User- defined variables are initialized to zero.)
RAM is restored from the flash PROM that contains the configuration values from the last cold start.
[See CAUTION in Power Up / Power Down (page 52).]
If the database configuration is found to be bad in both RAM and flash PROM,
Controller is set to a null default configuration. A system diagnostic INVALID CONFIG. is generated.
In all cases the controller performs a cold start when the controller mode is set to PROGRAM and then to RUN regardless of what method is used to change the mode. Whether the mode was set through the Configuration port or the operator interface, this action causes the PROGRAM mode to be cleared. Additionally, setting the mode switch to PROGRAM and then RUN allows you to change the controller mode if communications were disconnected to the Configuration port or operator interface while the controller was still in PROGRAM mode.
Release F | UMC800 Controller Installation and User Guide | 55 |
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