5/12/2017
TECH-538/D.W.O. 23160
Page 48 of 189
In the last example, the AO fault state parameters are configured as following:
•
IO_OPTS
set bit “Fault State to value”
•
STATUS_OPTS
set bits “Propagate Fault Bkwd” and “PV for BKCal_Out”
•
FSTATE_VAL
to “15”
•
FSTATE_TIME
to “5” (FSTATE_VAL is used after 5 seconds of FS is active)
In this situation a communication problem occurred on the “External AI” block (the OUT substatus is
“
NoComm_WithLastUsableValue
”). The AI.OUT is connected to the ICoT AO block, in the
AO.CAS_IN parameter. Then, the status of the AO.CAS_IN changed to
“
Bad::NoComm_WithLastUsableValue:NotLimited
” and the OUT substatus also changed to
“FaultStateActive”.
The ICoT AO actual mode changed to LO (Local Override mode) and the fault state action was initiated
and after 5 seconds (as configured in the parameter
FSTATE_TIME
) the AO.OUT, will change to the
constant value 15 (as configured in the parameter
FSTATE_VAL
).
It also shows that the substatus of the output BKCAL_OUT changed to “FaultStateActive” (bit “Propagate
Fault Bkwd” enabled as configured in the parameter
STATUS_OPTS
) and the value of the output
BKCAL_OUT is keeping at the constant value 15 (bit “PV for BKCal_Out” as configured in the parameter
STATUS_OPTS
).
Transducer block fault state parameters
In addition to the ICoT AO block standard FS parameters, there are 3 (three) parameters in the
Transducer block that can be used to configure the transducer actions in case of fault state detection:
PSNR_FSTATE_OPT
: whenever the Transducer block enters into a fault state (AO sends a BAD status to
the FINAL_VALUE parameter, for example) the device will control the valve according to what is defined
in this parameter.
•
0: Hold Last Value
•
1: Fail Closed
•
2: Fail Open
•
3: PSNR_FSTATE_VAL (uses the value configured in this parameter)
PSNR_OOS_OPT
: whenever the Transducer block enters into Out of Service (OOS) mode, the device will
control the valve according to what is defined in this parameter.
•
0: Hold Last Value
•
1: Fail Closed
•
2: Fail Open
•
3: PSNR_FSTATE_VAL (uses the value configured in this parameter)
PSNR_FSTATE_VAL
: if this parameter was chosen in any of the two previous parameters the state
assumed by any of the physical output will match the value configured in this parameter.
It is important to understand that this configuration does not replace the standard AO fault state
configurations as the Transducer block fault state is device specific.
The Transducer block will enter a fault state in the following situations:
•
Configuration error: AO is not using the Transducer block channel (when in Single or Double
Action);
•
Bad quality in the FINAL_VALUE parameter: example, AO in OOS mode.
Note
: see Section 11.4 for a complete list of blocks and parameters, including default values.
16
See also 9.2.3.12 for power failure condition
17
Although the parameter appears in the block list, the function is not implemented in the
version 4.1 or older
