Page 139 - Safety Risk Management for Medical Devices
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118 Safety Risk Management for Medical Devices
Figure 12.15 P-Diagram.
12.9.1 Input Signals
Input signals describe the items that the System needs to fulfill its objective. Examples
of Input Signals: energy, data, and materials.
12.9.2 System
The System is the entity that processes the Inputs, under the Control Factors and the
Noise Factors, and delivers the output.
12.9.3 Control Factors
Control Factors are the factors over which we have control, and can be changed as desired.
Examples: quantity of input materials, temperature of oven, duration of curing, etc.
12.9.4 Noise Factors
Noise Factors are things that can influence the output of the System, but over which
we do not have control. Examples: piece-to-piece variation, unintended customer
usage, environmental conditions.
Noise Factors are typically grouped in five categories:
• Piece-to-piece variation
• Change over time/mileage
• Customer usage/duty cycle
• External Environment
• System interaction
