Emerson Rosemount 3095, Reference Manual, Page: 92 / 130

Reference Manual
00809-0100-4716, Rev JA
May 2008
Rosemount 3095 MultiVariable
4-14
FIEL
DBUS
Control Selector Block (2500)
The control selector is used to select the most appropriate control output
based on a preconfigured criteria. The outputs of up to three PID blocks are
accepted as inputs to the control selector. The control selector selects which
control output to pass on to downstream blocks based on user configured
criteria such as maximum, minimum, middle, or first good.
Output Splitter Block (2600)
The output splitter is used to pass the output of a single PID block to one of
two analog output blocks depending on process conditions. Applications such
as temperature control may require either heating or cooling depending on
process conditions. The output splitter allows the output of the control PID to
be sent through two different AO blocks to two different final control elements.
RESOURCE BLOCK
FEATURES and
FEATURES_SEL
The parameters FEATURES and FEATURE_SEL determine optional
behavior of the 3095.
FEATURES
The FEATURES parameter is read only and defines which features are
supported by the 3095. Below is a list of the FEATURES the 3095 supports.
UNICODE
All configurable string variables in the 3095, except tag names, are octet
strings. Either ASCII or Unicode may be used. If the configuration device is
generating Unicode octet strings, you must set the Unicode option bit.
REPORTS
The 3095 supports alert reports. The Reports option bit must be set in the
features bit string to use this feature. If it is not set, the host must poll for
alerts.
FAULT STATE
The fault state condition is set by loss of communication to an output block,
when the fault state is promoted to an output block or a physical contact.
When fault state is set, then output function bocks will perform their FSTATE
actions. The Rosemount 3095 supports fault state action. The fault state
option bit must be set in the features bit to use this feature.
SOFT W LOCK and HARD W LOCK
Inputs to the security and write lock functions include the hardware security
switch, the hardware and software write lock bits of the FEATURE_SEL
parameter, the WRITE_LOCK parameter, and the DEFINE_WRITE_LOCK
parameter.
The WRITE_LOCK parameter prevents modification of parameters within the
device except to clear the WRITE_LOCK parameter. During this time, the
block will function normally updating inputs and outputs and executing
algorithms. When the WRITE_LOCK condition is cleared, a WRITE_ALM
alert is generated with a priority that corresponds to the WRITE_PRI
parameter.