Production of Polysilicon using a Modified Siemens Process

Post-condition: The appropriate action is taken based on the operating pressure. If
there is a dangerous condition, the alarm goes off, if not, then process goes on
as normal.
Scenario (2.3): Flow rate
Description: Flow rate sensors detect the difference between the desired operating
pressure and the actual operating pressure and alerts if there is a certain
difference between the two.
Primary Object: Flow rate sensor
Primary Actors: Streams of reactants and products throughout the system
Pre-condition: Desired operating flow rate and maximum allowable difference are
specified
Flow of Events:
1. Flow rate sensor takes reading of the operating temperature
2. Sensor compares operating temperature to desired pressure
3. Sensor compares the difference in the actual and desired pressure to the
specified allowable difference
4. If the difference is smaller, then alarm does nothing. If it is larger, the alarm
goes off.
Post-condition: The appropriate action is taken based on the operating pressure. If
there is a dangerous condition, the alarm goes off, if not, then process goes on
as normal.