How can I install ReliaSoft
software without having to provide user input during installation?
Standard software installations usually require that the user interact with
the computer during the installation process. For example, the user may need to
click Next > at certain stages of the installation, select I Accept
when presented with a license agreement or click Finish towards the end of
the installation process.
However, as of February 2011, the installation programs for many of ReliaSoft’s
products (including Weibull++,
will accept command-line options for performing unattended
installations—i.e., installations that do not require routine user inputs such as those
mentioned above. Unattended installations are especially useful when, for example,
multiple applications need to be installed onto multiple machines. In situations like
these, one can save time by running custom installation scripts that perform a series of
For a full listing of the affected ReliaSoft products and information on performing
unattended installations of these products, see Technical Support
document # RS40013.
How can I use the Duty Cycle
property in BlockSim?
In BlockSim the duty cycle property
allows you to model situations where the actual usage during the operation of a
component, subsystem or system is not identical to the usage for which you have data,
either from testing or from the field. This can include situations where the item:
Does not operate continuously (e.g., a DVD drive that was tested in continuous
operation, but in actual use within a computer accumulates only 18 minutes of usage
for every hour the computer operates).
Is subjected to loads that are greater than or less than the rated loads
(e.g., a motor that is rated to operate at 1000 rpm but is being used
at 800 rpm).
Is affected by changes in environmental stress (e.g., a laptop computer that is
typically used indoors at room temperature, but is being used outdoors in tropical
In these cases, continuous operation at the rated load is considered to be a duty
cycle of 1. Any other level of usage is expressed as a percentage of the rated load
value or operating time. Thus, for the examples given above:
The duty cycle for the DVD drive is 18 min / 60 min = 0.3.
The duty cycle for the motor is 800 rpm / 1000 rpm = 0.8.
For the laptop, the duty cycle is determined based on the intended operating
conditions and on engineering knowledge about how increased temperature and
humidity affect the system. In this case, suppose that testing has shown that the
tropical conditions increase the stress on the components of the laptop by a factor
of 1.5. Thus, the duty cycle is 1.5.
In BlockSim 7, the duty cycle property can be applied to blocks in RBDs and
to operational phases in phase diagrams.
In RBDs, you can assign various duty cycles to individual components in a diagram.
Alternatively, you can assign the same duty cycle to all components in a diagram, thereby
applying that duty cycle to the entire assembly or system represented by the diagram. In
phase diagrams, you can assign various duty cycles to individual operational phases to
represent varying use levels during the system mission (e.g., the varying stress on an
aircraft engine during taxi, take-off, cruising and landing). You can also use a phase
diagram as a quick way to apply a duty cycle to an entire RBD by creating a phase
diagram that contains a single operational phase and assigning a duty cycle to the
In cases where multiple duty cycles apply, their effect is compounded. This can happen
either within an RBD or where a phase duty cycle interacts with a duty cycle within the
RBD. Assume, for example, that the DVD drive mentioned above is part of the laptop also
mentioned above. If you were to model the tropical use conditions within an RBD, you
would need to multiply the duty cycle for every component in the laptop by the laptop’s
duty cycle of 1.5. For components that normally operate continuously at rated load in
the laptop (i.e., components that have a duty cycle of 1), the duty cycle would
be 1 x 1.5 = 1.5. The duty cycle for the DVD drive would be 0.3 x 1.5 = 0.45. If you
chose, instead, to use a phase diagram to apply the laptop duty cycle, all duty cycles
in the RBD would be at their original values (e.g., the DVD drive’s duty cycle would
be 0.3). The multiplication of duty cycles would be automatically performed upon
simulation of the phase diagram.