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{{Template:BSExampleSim| Example 5}}
#REDIRECT [[Example_Using_SCT_for_Standby_Rotation]]
 
== Standby Rotation Example  ==
 
==== Purpose  ====
 
This example illustrates the use of state change triggers [http://www.reliawiki.org/index.php/BlockSim_8:_State_Change_Triggers#State_Change_Triggers SCT] in BlockSim Version 8 by using a simple standby configuration. ''Note that this example could also be done using the standby container functionality in BlockSim.''
 
More specifically the following settings are illustrated:
#State Upon Repair: Default OFF unless SCT overridden
#Activate a block if any item from these associated maintenance group(s) goes down<br>
 
 
==== Statement ====
 
Assume three devices A, B and C in a standby redundancy (or only one unit is needed for system operation). The system begins with device A working. When device A fails B is turned on and repair actions initiated on A. When B fails C is turned on and so forth.
 
 
 
==== BlockSim Solution  ====
 
The BlockSim model of this system is shown in the Figure below.
 
[[Image:Blocksim Example Rotation example.png|thumb|center|361px]]
 
 
 
*The failure distributions of all three blocks follow Weibull distribution with Beta = 1.5 and Eta = 1,000.
*The repair distribution of three blocks also follows Weibull distribution with Beta = 1.5 and Eta = 100.
*After repair, they are "as good as new".
 
 
There are three maintenance groups, 2_A, 2_B and 2_C set as follows:
 
 
*Block A belongs to maintenance group 2_A.
**It has state change trigger.
***The initial state is ON and the state upon repair is "Default Off Unless overridden".
***If any item from maintenance group 2_C goes down, then activate this block.
 
 
 
*Block B belongs to maintenance group 2_B.
**It has state change trigger.
***The initial state is OFF and the state upon repair is "Default Off Unless overridden".
***If any item from maintenance group 2_A goes down, then activate this block.
 
 
*Block C belongs to maintenance group 2_C.
**It has state change trigger.
***The initial state is OFF and the state upon repair is "Default Off Unless overridden".
***If any item from maintenance group 2_B goes down, then activate this block.
 
 
*All blocks A, B and C are as good as new after repair.
 
==== System Events  ====
 
 
 
The system event log is shown Block Up/Down plot below, for a single run through the simulation algorithm  and is as follows:
 
#At 73, Block A fails and activates Block B.
#At 183, Block B fails and activates Block C.
#At 215, Block B is done with repair. At this time, Block C is operating, according to setting, Block B is standby.
#At 238, Block A is done with repair. At this time, Block C is operating. Thus Block A is standby.
#At 349, Block C fails and activates Block A.
#At 396, Block A fails and activates Block B.
#At 398, Block C is done with repair. At this time, Block B is operating. Thus Block C is standby.
#At 432, Block A is done with repair. At this time, Block B is operating. Thus Block A is standby.
#At 506, Block B fails and activates Block C.
#At 515, Block B is done with repair and keep standby because Block C is operating.
#At 536, Block C fails and active Block A.
#At 560, Block A fails and active Block B.
#At 575, Block B fails and put a request to active Block C. However, Block C is under repair at the time. Thus when Block C is done with repair at 606, the OFF setting is overwritten and it is operating immediately
#At 661, Block C fails and put a request to active Block A. However, Block A is under repair at the time. Thus when Block A is done with repair at 699, the OFF setting is overwritten and it is operating immediately.
#Block B and Block C are done with repair at 682 and at 746 respectively. However, at these two time point, Block A is operating. Thus they are both standby upon repair according to settings.
 
 
 
[[Image:Block Up Down plot for rotation example.png|thumb|center|500px]]
 
[[Category:BlockSim_Examples]]

Latest revision as of 09:37, 31 July 2012