Valve Position Proximity Detection; Field Value Processing - Emerson Fisher Fieldvue DVC6030f Instruction Manual

DVC6000f Series
DISCRETE INPUT SET
5
Figure 5-32. Discrete Input Proximity Detection Function

Valve Position Proximity Detection

Channels 30 through 33 provide valve position
proximity detection for the DI block. The transducer
block Travel Alrt Pt and Travel Alrt DB parameters are
also used with the valve position proximity, but they
provide a different function. The Travel Alrt Pt for the
selected channel determines the center point for the
position to be detected. The Travel Alrt DB for the
selected channel sets the upper and lower trigger
points, or the width of the proximity detection band. A
1% deadzone exists above and below this band that
the travel must exceed to clear the detected position.
Figure 5-32 illustrates the operation of the proximity
detection function. Travel Alrt Pt refers to Tvl Lo Alrt
Pt, Tvl Hi Alrt Pt, Tvl Lo Lo Alrt Pt, and Tvl Hi Hi Alrt Pt
in table 5-78. Travel Alrt DB refers to Tvl Lo Alrt DB,
Tvl Hi Alrt DB, Tvl Lo Lo Alrt DB, and Tvl Hi Hi Alrt DB
in table 5-78.
0= Not Active, 1= Active
Table 5-78 lists the transducer block parameters used
for proximity detection with DI block channels 30
through 33.

Field Value Processing

The Invert bit of the IO_OPTS [13] parameter may be
used to logically invert the value of FIELD_VAL_D [17]
before it is stored as PV_D [7]. PV_FTIME [16] may
be used to set the length of time that FIELD_VAL_D
[17] must be in a new state before that new state is
reflected in PV_D. The
5-160
Table 5-77. Transducer Block Parameters Used with Discrete
Input Function Block Channels 26 through 29 (Variable Limit
DISCRETE INPUT
CLEARED
Transducer Block
DEADZONE, 1%
Tvl Lo Lo Alrt Pt
OF TRAVEL
Tvl Lo Lo Alrt DB
Tvl Lo Alrt Pt
TRIGGER POINT FOR
DOWNWARD VALVE
Tvl Lo Alrt DB
TRAVEL DETERMINED
BY TRAVEL ALERT
Tvl Hi Alrt Pt
DEADBAND
Tvl Hi Alrt DB
Tvl Hi Hi Alrt Pt
CENTER POINT OF
Tvl Hi Hi Alrt DB
PROXIMITY DETECTION
DETERMINED BY
TRAVEL ALERT POINT
Table 5-78. Transducer Block Parameters Used with Discrete
TRIGGER POINT FOR
UPWARD VALVE TRAVEL
Transducer Block
DETERMINED BY TRAVEL
ALERT DEADBAND
Tvl Lo Lo Alrt Pt
Tvl Lo Lo Alrt DB
Tvl Lo Alrt Pt
Tvl Lo Alrt DB
Tvl Hi Alrt Pt
Tvl Hi Alrt DB
Tvl Hi Hi Alrt Pt
Tvl Hi Hi Alrt DB
PV_D [7] value goes to the mode switch where it
becomes OUT_D [8] when the actual mode is AUTO.
OUT_D [8] is also tested for an alarm state.
Alarm Detection
To select the state that initiates an input alarm, and to
set discrete alarm substatus in the output, configure
the DISC_LIM [23] parameter. You can enter any
value between 0 and 255. A value of 255 disables the
alarm. When OUT_D [8] matches the DISC_LIM [23]
state, the discrete value of an alarm is set.
Switch)
Parameter Function
Parameter
Lo Lo Limit Switch trip point
Lo Lo Limit Switch deadband
Lo Limit Switch trip point
Lo Limit Switch deadband
Hi Limit Switch trip point
Hi Limit Switch deadband
Hi Hi Limit Switch trip point
Hi Hi Limit Switch deadband
Input Function Block Channels 30 through 33
Parameter Function
Parameter
Lo Lo Proximity Detection Center Point
Lo Lo Proximity Detection Width
Lo Proximity Detection Center Point
Lo Proximity Detection Width
Hi Proximity Detection Center Point
Hi Proximity Detection Width
Hi Hi Proximity Detection Center Point
Hi Hi Proximity Detection Width
Note
Invert is the only I/O option that the DI
block supports. You can set the I/O
option only when the block mode is
Out of Service.
March 2006