INFICON IC/5 Thin Film Deposition Controller - Manual (Page 221)

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IC/5 Operating Manual
10.3.2.3 Logic Statement Directory
The Logic Statements are broken down into 3 sections. The first section, comprised
of statements 1 through 23, deals primarily with the pump down sequence during
automatic processing (i.e. when the key switch is in the Auto position). These
Statements also contain some fail safe conditions to stop the automatic process if
something goes wrong and to prevent, for example, the Foreline Valve and
Roughing Valve from being open at the same time.
The second section is comprised of statements 24 through 29. These statements
place the User-Defined Messages onto the IC/5 display at appropriate times during
the pump down cycle. The third section, statements 30 through 43, controls the
actual deposition process. This involves turning the electron beam gun high
voltage on and off, monitoring the chamber pressure to determine when to begin
the deposition and issuing START commands to begin the process and step
through the layer sequence. This section also contains statements for venting the
chamber at the end of the deposition process, after the cool down period has
expired. Messages indicating the status of the deposition process are also
managed in this section.
NOTE: Statements 1 Through 23 Control the Automatic Pump Down Cycle.
Figure 10-6 Statement 1
Statement 1 is designed to identify to the IC/5 that the vacuum system is ready for
automatic process control. This is indicated by setting Timer 1. Other Logic
Statements will evaluate true only if Timer 1 has expired. Statement 2 which is the
antithesis of Statement 1, cancels Timer 1 to prevent automatic processing. The
Alarm Relay is also turned ON to indicate to the Operator or Process Engineer that
the vacuum system requires attention. This relay may be connected to an Audio or
Visual Alarm. The Connectors, Mechanical Pump On, Auto, and Gauges inputs
must be activated in order for Timer 1 to be started and for the Alarm Relay to be
closed.
Figure 10-7 Statement 2
Statement 2 is designed to detect whether the system is not ready for automatic
process control or whether something goes wrong during the process. The action
taken is to stop the pump down or venting process by closing the foreline, roughing
and vent valves and canceling Timer 1.