Honeywell ST700 - SOFT W LOCK and HARD W LOCK

Revision 2.0 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide Page 17
SOFT W LOCK and HARD W LOCK
There are two types of write locks: Hardware write lock and Software write lock. The
software write lock is used to lock the device. The software write lock does not need a
jumper. A hardware write lock is provided with a jumper in the device to perform the write
lock operation.
If the WRITE_LOCK parameter is set, it prevents any external change to the static or non-
volatile database in the Function Block Application of the resource. Block connections and
calculation results proceeds normally but the configuration is locked. A hard write lock is
provided by a jumper in the device as indicated in the FEATURES bit string. Clearing
WRITE_LOCK generates the discrete alert WRITE_ALM at the WRITE_PRI priority.
If the soft write lock bit is not set as True in the features bit strings, the writing to the
parameter WRITE_LOCK is rejected by the device. For devices that support hard write
lock and have the associated FEATURE_SEL attribute enabled, the parameter
WRITE_LOCK is only an indicator of the state of write-lock. The writing to
WRITE_LOCK is rejected by the device.
Software write lock
To activate write lock, the soft write lock supported bit in FEATURE_SEL must be set,
and then set the WRITE_LOCK to locked. To deactivate write lock, set the
WRITE_LOCK to unlocked.
Hardware write lock
To activate write lock, the hard write lock supported bit in FEATURE_SEL must be set,
and additionally the write lock jumper must be in the correct position as determined by the
manufacturer. When this is detected by the device, WRITE_LOCK is set to locked. If
hard write lock is enabled in FEATURE_SEL, the configured value of soft write lock has
no impact on device operation. To deactivate write lock, the jumper must be changed as
FEATURE_SEL is not writeable during write lock. Once the device detects the change in
jumper position, the write-lock is disabled and WRITE_LOCK is set to 1.
Install Date
When the device is connected to the master/host, the time at which the device is powered
up is taken as the install date. It is a read-only parameter.