PROCESS SETUP AND ACCEPTANCE
P
ROCESS
M
ANUAL
As the DPC has been designed to remember the last settings until they are changed, it is vital to verify the
settings in the step one branches to.
For example, in step 3 of the schematic above a Branch on Alarm y has been programmed. If this Alarm y
occurs for more than 3 consecutive seconds then the DPC will branch to step 5. While branching it
bypasses any changes programmed in step 4.
3.3.4
Handling alarms with the Abort command
An Abort command can be issued in two ways:
1) programmed in a process recipe
in a specific step
2) manually by an operator
at any time
If any Abort command is issued the DPC will stop the running process recipe. The DPC will return to
step 0 of the process recipe, either directly or via an Abort Recipe. An Abort recipe also contains steps
and is used to bring the tube in a safe condition.
Note: An Abort recipe must be programmed such that a tube is automatically brought to a SAFE
situation.
As step 0 of the process recipe is the target of an Abort command it should be programmed to contain a
safe condition. In some applications however, such as in a 24hr production environment, this is likely not
the case.
Therefore, the use of an Abort recipe must be applied as soon as in the process recipe potentially
dangerous situations occur when that process recipe is aborted and brought back to step 0.
3.3.4.1 Abort command in a specific step
The programmed Abort command can be used similarly to the Branch on Alarm command. In fact, an
Abort command could be interpreted as a Branch on Alarm to Step 0 command.
Figure 3-2
: Abort command initiated from a specific alarm condition without (left) and with (rightt) the use of an
Abort recipe
3.3-2
