Toshiba RUAGP Series Original Owner's Manual page 60

10. Protection control for risk distribution
The protection control feature of the module controller stops a module operation if it determines that the module
cannot continue to operate any longer, based on the states of the protective devices and sensors. If a given
circuit in a module has failed, another circuit in that module automatically initiates backup operation unless all the
circuits in it fails. (Depending on protection control (see the error code list on the next page), the module
controller stops all the circuits or only the failed circuit.) Additionally, in the event that a module has failed,
another module can automatically initiate backup operation; in this case, however, since fewer modules are
available for active operation, the maximum system performance is lowered. If the percentage of failed circuits
(i.e., the ratio of failed circuits in a system
programmed threshold, the module controller displays and signals a major fault indication. This threshold is
programmable with the module controller. If the percentage of failed circuits is greater than the threshold, the
module controller indicates a major fault. If it is less than the threshold, the module controller indicates a minor
fault. In both cases, one or more working modules are activated as a backup. The factory default for the
threshold is 100%. Modify the percentage as necessary.
*1 Failed circuits in a system include:
 Circuits that fail while running in the Remote mode
 Circuits that fail while running in the Unit mode
 Circuits of the modules that are idle in the Unit mode
 Circuits that are idle in the Unit and Remote modes
*2 The number of all circuits in a system means:
In Cooling mode: Number of circuits of cooling-only and heat pump modules
In Heating mode: Number of circuits of heat pump and heat machine modules
(1) Major faults: When the percentage of failed circuits is greater than the threshold
 The unit controller for the failed module shows a module error code on the LED display.
 The LCD monitor of the module controller shows the failed module no. and circuit name(s), and an error
code. The module controller also provides major-fault signalling.
 In the event of a major fault, the module controller activates a normal module(s) in the system as a backup.
 If the number of the failed circuits in a system has fallen below the threshold as a result of a fault reset by the
unit controller, the major fault status is reset and changed to a minor fault.
(2) Minor faults: When the percentage of failed circuits is less than the threshold
 The unit controller for the failed module shows a module error code on the LED display.
 The LCD monitor of the module controller shows the failed module no. and circuit name(s), and an error
code. The module controller also provides minor-fault signalling.
 In the event of a minor fault, the module controller activates a normal module(s) in the system as a backup.
 If all the failed circuits in a system have been reset as a result of a fault reset by the unit controller, the minor
fault status is reset.
In the event of a module failure, the LCD monitor of the module controller and the LED display on the unit
controller of the failed module show an error code.
*1
to the number of all circuits in a system*
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2
) has risen above the