Emerson FIELDVUE DVC6200f, Instruction Manual

Page: 161 / 326

OS Function Block
November 2010 149
(X
11
, Y
11
)
SP
Split Range Sequencing
(X22 , Y22)
(X
12
, Y
12
)
OUT_1
OUT_2
0%
50% 100%
100%
100%
OUT_2
OUT_1
100%
0% 0%
0% 50%
(X
12
, Y
12
) (X
22
, Y
22
)
(X
11
, Y
11
)
(X
21
, Y
21
) (X
21
, Y
21
)
SP
X
X
Y
Y
Figure 4-18. Split Range and Sequence Operation
Table 4-46. OUT_ARRAY Coordinates
Index Coordinate
0 Y
11
−
Value of OUT_1 at X
11
1 Y
12
−
Value of OUT_1 at X
12
2 Y
21
−
Value of OUT_2 at X
21
3 Y
22
−
Value of OUT_2 at X
22
A configuration error is set in BLOCK_ERR and the
actual mode of the block goes to Out of Service if the
X values have any of the following conditions: X
21
<
X
11
, X
12
< = X
11
, X
22
< = X
21
.
Refer to figure 4-19 for an example of LOCKVAL =
true, and figure 4-20 for an example of LOCKVAL =
false. The parameter LOCKVAL provides an option to
specify whether OUT_1 remains at its ending level
when control is switched to OUT_2, or goes to Y
11
. If
LOCKVAL is true, OUT_1 remains at its ending value
when X is greater than X
12
. If LOCKVAL is false, then
OUT_1 goes to Y
11
when X is greater than X
12
.
0%
SP
OUT 1
OUT 2
OUT 1 remains at
end point when OUT_2
is non-zero
50%
100%
Figure 4-19. OUT with LOCKVAL True
OUT 1 OUT 2
0%
SP
50%
100%
OUT_1 goes to zero
OUT_2 becomes
Figure 4-20. OUT with LOCKVAL False
Some hysteresis in the switching point may be
required because the output may change by a full
stroke of the valve. HYSTVAL [12] contains the
amount of hysteresis. If X < = X12
−
HYSTVAL,
OUT_1 may be determined by the calculated y value.
If X12
−
HYSTVAL < X < X12 and X has not reached
X12 since it was less than X12
−
HYSTVAL, OUT_1
may be determined by the calculated y value. If
X12
−
HYSTVAL < X < X12 and X has reached X12
since it was less than X12
−
HYSTVAL, OUT_1 may be
determined by the LOCKVAL setting. If X12 < X,
OUT_1 may be determined by the LOCKVAL setting.
Initialization and Back Calculation
Requirements
Refer to figure 4-21, Output Splitter Configuration,
where:
PID1 = Upstream driving controller or function block.
4