EP03-300-200
December,
2003
Release 200
Version 1.0
Experion PKS CEE-based Controller Specifications and Models
10
Sequential Control
Due to its rich set of standard features, SCMs greatly simplify
batch
logic implementation. The SCM
implementation follows the S88.01 standard. Standard features include
abnormal handling,
providing
an alternative sequence execution for user specified abnormal conditions. Abnormal handlers support
restart capabilities, re-starting the sequence from the position it was left or any other Step the process
requires to continue. Standard Abnormal handlers include: Checking, Interrupt, Restart, Hold, Stop
and Abort. Each sequence supports up to 50 recipe parameters. These include a range, material
code and scale option. In addition, it has 50 history parameters for reporting the amount of actual
dosed material and/or reached process conditions. The
mode track
option allows for different
operating philosophies. Devices, such as motors, pumps, and controllers, will follow SCM mode
changes allowing either operator or sequence device control. The devices can also be pre-configured
with the action required after an SCM start, abnormal situation or restart. This reduces the SCM step
configuration.
One feature of particular importance is the
Common SCM
function. A Common SCM is one that can
control several equipment units, one at a time, depending upon the unit selected. It saves
implementation, test and maintenance time required to support the application. The selected unit may
be determined at configuration time or changed dynamically during run time. An example application
might be header dosing in a batch plant. SCMs, including this Common SCM function, are fully
integrated into Honeywell’s
TotalPlant
Batch package for flexible batch operation.
