Emerson Fisher FIELDVUE DVC6000f Instruction Manual page 340

DVC6000f Digital Valve Controllers
Table D-2. Examples of Block Mode Combinations and
Operational statuses for an Instrument with Standard Control
Operational Status
Initial Setup and
calibration
Modification of some
transducer block
parameters
Constant valve position
control
PID Single-loop control
PID Cascade-loop control
1. TB=Transducer Block
Cascade (Cas)—The block performs the specified
calculations based on the set point from another block
via the cascade input parameter and outputs the
result. Any block outputs continue to update.
Remote Output (ROut)—The block outputs are set to
the value of the remote output parameter that is
written by a host computer or others. To prevent a
sudden change in output, the block's calculations are
initialized when a change in mode occurs.
Remote Cascade (RCas)—The block performs the
specified calculations based on a set point from a host
computer or others via the remote cascade input and
outputs the result. If the block has any outputs, these
continue to update.
Examples of Modes for Various
Operational Statuses
D
Table D-2 shows examples of block mode
combinations in a digital valve controller (however it
does not show all combinations). When a block
changes mode or the data status signal changes for
some reason, the other blocks connected to that block
identify the change by detecting the change in status
of an input signal, and change their modes too. For
example, when the data status of BKCAL_IN in a PID
block changes to bad, the PID block automatically
changes its mode to Iman to initialize the control of its
downstream block.
The respective modes to which each block should
enter upon occurrence of a communication error and
at a restart, and the handling of signals in each mode
may be defined in the block's option parameters such
as IO_OPTS and STATUS_OPTS. For details, see
the detailed descriptions of each function block.
D-6
Blocks
PID AO
− − −
OOS
− − −
IMan Manual
− − −
Auto
Auto Cas
Primary PID, Auto
Cas
Secondary PID, Cas
Table D-3. Status Attribute Quality and Substatus Components
Quality
Good (NC)
(1)
TB
Good (NC)
Good (NC)
OOS
Good (NC)
Good (NC)
Good (NC)
Good (NC)
Auto
Uncertain
Auto
Uncertain
Uncertain
Auto
Uncertain
Uncertain
Uncertain
Uncertain
Good (C)
Good (C)
Good (C)
Good (C)
Good (C)
Good (C)
Good (C)
Good (C)
Bad
Bad
Bad
Bad
Bad
Bad
Bad
Bad
(NC)=(Non-cascade)
Device Descriptions
Device Descriptions are specified definitions that are
associated with blocks. Device descriptions provide for
the definition and description of blocks and their
parameters.
Device descriptions may also include a set of
processing routines called Methods. Methods provide
a procedure for accessing and manipulating a series
of parameters within a device, such as for setup and
calibration. Methods are used for a variety of functions
including automatic calibration, setting protection and
setting up the instrument. These Methods are a
predetermined sequence of steps for information
required to setup, calibrate, and perform other
functions on the instrument.
Substatus
Non-specific
Active Block Alarm
Active Advisory Alarm
Active Critical Alarm
Unack Block Alarm
Unack Advisory Alarm
Unack Critical Alarm
Non-specific
Last Usable Value
Substitute/Manual Entry
Initial Value
Sensor Conversion not Accurate
Engineering Unit Range Violation
Sub-normal
Non-specific
Initialization Acknowledge
Initialization Request
Not Invited
Not Selected
Local Override
Fault State Active
Initiate Fault State
Non-specific
Configuration Error
Not Connected
Device Failure
Sensor Failure
No Comm, with LUV
No Comm, no LUV
Out of Service
(C)= (Cascade)
December 2009