UM353-1B Function Blocks
April 2012
3-47
3.2.45 LL_ - Lead/Lag
LL_ function blocks provide both lead and lag functions.
The block can function as lag only by setting the TLEAD
time to 0.0. The lag function is always active and has a
minimum setting of 0.01 minutes.
Input E asserted high (1) will enable the Lead/Lag
function. When asserted low (0), the Lead/Lag function
will be bypassed and the output will be set equal to the
input. If input E is not configured, the block will be
enabled.
BLOCK DIAGRAM
O1
E
A
t
Lead
+ 1
t
Lag
+ 1
E
nable
A
nalog Input
O
utput
1
.
POWER UP - During a warm or cold start, the dynamic elements and the output will be initialized to the value of
the current input on the first scan.
3.2.46 LMT_ - Limit
LMT_ function blocks are used to limit a real signal.
Input A will normally pass through the function block to
the output O1. If the input exceeds one of the limits, the
block will output the limit value.
If the HI LIMIT is set lower than the LO LIMIT, the block
will output the high limit value. The output statuses will
be high (1) when the block is in a limit condition.
BL
K DIA
RAM
HI SELECTOR
LO SELECTOR
HI LIMIT
A
O1
LO LIMIT
HS
LS
O
utput
1
H
igh limit
S
tatus
L
ow limit
S
tatus
.
.
A
nalog Input
LEAD/LAG
G
T
T
L
E
T
ime -
LAG
(min)
(S)
....... 0.01 - 10000.0 (0.10)
T
ime -
LEAD
(min)
(S)
..... 0.00 - 10000.0 (0.00)
O1
O
utput
1
LEAD/LAG
LL_
ESN =
000
A
L
A
E
E
nable
I
I
N
N
P
P
U
U
T
T
A
E
INPUT E
(H)
...........
loop tag.block tag.output (null
)
ESN
E
xec.
S
eq.
N
o.
(H)
................. 001 to 250
A
D
INPUT A
(H)
..........
loop tag.block tag.output (null)
Input
A
LIMIT
TI
H
I
O
L
I
N
U
A
HI
gh
LIMIT
(S)
........................... Real (100.00)
LO
w
LIMIT
(S)
........................... Real (0.00)
INPUT A
(H)
.....
loop tag.block tag.output (null)
HS
H
igh
S
tatus
LIMIT
LMT_
ESN =
000
I
M
L
T
P
A
L
I
M
I
T
ESN
E
xec.
S
eq.
N
o.
(H)
............ 001 to 250
O1
O
utput
1
L
ow
S
tatus
LS
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