Fisher FIELDVUE DVC6200f Instruction Manual page 174

Detailed Setup—AI Function Block
July 2013
Figure 4‐24. Analog Input Function Block Schematic
ANALOG
MEASUREMENT
ACCESS
ANALOG
MEAS.
CHANNEL
CONVERT
SIMULATE
FIELD_VAL
OUT_SCALE
XD_SCALE
NOTES:
OUT_D = BLOCK OUTPUT VALUE AND STATUS
OUT_D = DISCRETE OUTPUT THAT SIGNALS A SELECTED ALARM CONDITION.
Process Alarm detection is based on the OUT [8] value. You can configure the alarm limits of the following standard
alarms:
D High (HI_LIM [28])
D High high (HI_HI_LIM [26])
D Low (LO_LIM [30])
D Low low (LO_LO_LIM [32])
In order to avoid alarm chattering when the variable is oscillating around the alarm limit, an alarm hysteresis in percent
of the PV [7] span can be set using the ALARM_HYS [24] parameter. The priority of each alarm is set in the following
parameters:
D HI_PRI [27]
D HI_HI_PRI [25]
D LO_PRI [29]
D LO_LO_PRI [31]
Alarms are grouped into five levels of priority, as shown in table 4‐53.
Table 4‐53. AI Function Block Alarm Priorities
Priority Number
0 The priority of an alarm condition changes to 0 after the condition that caused the alarm is corrected.
1 An alarm condition with a priority of 1 is recognized by the system, but is not reported to the operator.
An alarm condition with a priority of 2 is reported to the operator, but generally does not require operator attention (such as
2
diagnostics and system alerts).
3-7 Alarm conditions of priority 3 to 7 are advisory alarms of increasing priority.
8-15 Alarm conditions of priority 8 to 15 are critical alarms of increasing priority.
1. The priority classes "advise" and "critical" have no relationship to PlantWeb Alerts.
172
ALARM_TYPE
HI_HI_LIM
HI_LIM
ALARM
LO_LO_LIM
DETECTION
LO_LIM
ALARM_HYS
LOW_CUT
CUTOFF FILTER
L_TYPE
PV_FTIME
IO_OPTS
PV
STATUS
CALC.
MODE
STATUS_OPTS
Priority Description
Instruction Manual
OUT_D
OUT
(1)
D103412X012