PROCESS SETUP AND ACCEPTANCE
P
ROCESS
M
ANUAL
3.3 Alarm handling with Branch and Abort commands
3.3.1
Introduction
The Tempress Systems, Inc. process controller, DPC, has some special features that allow alarm
conditions to be handled automatically.
A process recipe is made of steps, and within one step several commands can be programmed.
Alarm conditions can be set, and when these conditions are compromised a very specific alarm message is
generated. It is up to the process engineer to decide whether or not action is required on the specific alarm
message.
Three options are available to the process engineer:
1) do nothing, the process recipe continues as programmed
2) branch to another step within the process recipe
3) abort the process recipe, which brings the tube back to step 0 of that process recipe.
The Branch on Alarm command is issued after 3 seconds of consecutive alarm condition and jumps to the
designated step within the same process recipe.
The Abort on Alarm command is issued after 30 seconds of consecutive alarm condition and aborts the
process recipe, either directly into step 0 of that process recipe, or via an assigned Abort Recipe.
3.3.2
Do nothing with an alarms
Some types of alarm conditions are not important enough to stop a running process. These alarms still
need to be fixed, though, and can be traced in long term history using the Tempress Systems, Inc. host
computer system TSC-2 and short term history using the touchscreen alarm status screen.
An example of this type of alarm is a temperature limit alarm during ramping, or a bubbler level alarm
while the bubbler is not used in this particular process recipe.
3.3.3
Handling alarms with the Branch command
Any kind of alarm can be handled by the Branch command. It is often used to finish a process recipe
trying to save valuable process wafers.
Figure 3-1
: Branch command jumps to a specified step number
3.3-1
