Emerson Rosemount 3144P, Reference Manual

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138
Reference Manual
00809-0100-4021, Rev JA
Configuration
April 2017
Configuration
4.5 Resource block
4.5.1 Features and Features_Sel
The FEATURES and FEATURE_SEL parameters determine optional behavior of the transmitter.
FEATURES
The FEATURES parameter is read only and defines which features are supported by the transmitter. The
list of FEATURES the transmitter supports is listed below.
UNICODE
All configurable string variables in the transmitter, 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 transmitter supports alert reports. To use this feature, the Reports option bit must be set in the
features bit string. If it is not set, the host must poll for alerts.
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. The block will function normally updating inputs and outputs and executing
algorithms while WRITE_LOCK is in use. When the WRITE_LOCK condition is cleared, a WRITE_ALM alert
is generated with a priority that corresponds to the WRITE_PRI parameter.
The FEATURE_SEL parameter enables the user to select a hardware or software write lock or no write lock
capability. To use the hardware security function, enable the HW_SEL bit in the FEATURE_SEL parameter.
When this bit has been enabled, the WRITE_LOCK parameter becomes read only and reflects the state of
the hardware switch. In order to enable the software write lock, the SW_SEL bit must be set in the
FEATURE_SEL parameter. Once this bit is set, the WRITE_LOCK parameter may be set to “Locked” or “Not
Locked.” Once the WRITE_LOCK parameter is set to “Locked” by either the software or the hardware
lock, all user requested writes as determined by the DEFINE_WRITE_LOCK parameter will be rejected.
The DEFINE_WRITE_LOCK parameter allows the user to configure whether the write lock functions (both
software and hardware) control writing to all blocks, or only to the resource and transducer blocks.
Internally updated data such as process variables and diagnostics will not be restricted by the security
switch.