Fault State Conditions Detected By Ao Block; Fault State Conditions Detected By Transducer Block - GE Baker Hughes Masoneilan SVI FF Installation And Operation Manual

Fault State Conditions Detected by AO Block

The AO block monitors multiple conditions and goes to Fault State if:
The CAS_IN input is not updated for a user-configurable number of block executions in
a row and the block is in CAS (cascade) mode.
The status of the received data in CAS_IN is Initiate Fault State and the block is in CAS
mode.
The RCAS_IN input is not updated and the block is in RCAS (remote cascade) mode.
The status of the received data in RCAS_IN is Initiate Fault State and the block is in
RCAS mode.
The Fault State related I/O option (IO_OPTS) determines the reaction of the Analog Output
function block - whether the action is simply to hold, or to move to FSTATE_VAL. If I/O Option
IO_OPTS bit 6 (Fault State to value) is:
NOT set, the OUT parameter of the block remains unchanged - the valve keeps the
position set before the fault state is detected.
Set, the OUT parameter of the block remains unchanged for the duration defined in
FSTATE_TIME parameter. If the conditions causing the Fault State persist, the OUT
parameter is then set to the value defined in FSTATE_VAL. FF specification
recommends that FSTATE_VAL value is close to the de-energized position.
The Transducer block follows the setpoint received from the output block. When I/O Option
IO_OPTS bit 6 is:
NOT set - the setpoint follows the same point.
Set - the setpoint tracks the FSTATE_VAL position.
Once the condition causing Fault State is removed, the normal processing is restored and the
block follows the setpoint provided in the input.

Fault State Conditions Detected by Transducer Block

In AUTO mode, the transducer block monitors the setpoint received from the AO.OUT
parameter via the TB.FINAL_VALUE.
If the value received has bad status (bad value received from communications, AO block in
OOS mode, etc.) or if the value is not updated (AO is not scheduled or a changed configuration
is incorrect), the behavior in the TB is defined by the XD_FSTATE.XD_FSTATE_OPT and
XD_FSTATE.FSTATE_TIME parameters. For the first several seconds (defined by
XD_FSTATE.FSTATE_TIME), the valve follows the last good setpoint. After that,
XD_FSTATE.XD_FSTATE_OPT defines the behavior as follows:
XD_FSTATE.XD_FSTATE_OPT = 0: the valve continues staying in position.
XD_FSTATE.XD_FSTATE_OPT = 1: the valve goes to fully closed position (expected to be
near 0%, subject to stops tolerances).
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