Emerson Rosemount 752 FOUNDATION, Справочное руководство

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12
Reference Manual
00809-0100-4377, Rev CA
Configuration
January 2018
Configuration
2.8 Resource block
2.8.1 FEATURES and FEATURES_SEL
The parameters FEATURES and FEATURE_SEL determine optional behavior of the Rosemount 752.
FEATURES
The FEATURES parameter is read only and defines which features are supported by the Rosemount 752.
Below is a list of the FEATURES the Rosemount 752 supports.
UNICODE
All configurable string variables in the Rosemount 752, 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 Rosemount 752 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.
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.
The FEATURE_SEL parameter enables the user to select a hardware or software write lock or no write lock
capability. To enable 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 will
reflect 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 shall
be rejected.
The DEFINE_WRITE_LOCK parameter allows the user to configure whether the write lock functions (both
software and hardware) will 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.