15 Standard
The block library can be found for download in the ‘Service/Support’ area of
www.vipa.com at ‘Downloads è VIPA Lib’ as ‘Block library Standard - SW90JS0MA’ .
The library is available as packed zip file. As soon as you want to use these blocks you
have to import them into your project.
Ä
Chap. 5 ‘Include VIPA library’ page 69
15.1 Converting
15.1.1 FB 80 - LEAD_LAG - Lead/Lag Algorithm
The Lead/Lag Algorithm LEAD_LAG function block allows signal processing to be done
on an analog variable. An output OUT is calculated based on an input IN and the speci-
fied gain GAIN, lead LD_TIME, and lag LG_TIME values. The gain value must be greater
than zero. The LEAD_LAG algorithm uses the following equation:
Typically, LEAD_LAG is used in conjunction with loops as a compensator in dynamic
feed-forward control. LEAD_LAG consists of two parts. Phase lead shifts the phase of the
function block’s output so that it leads the input whereas phase lag shifts the output so
that it lags the input. Because the lag operation is equivalent to an integration, it can be
used as a noise suppressor or a low-pass filter. A lead operation is equivalent to a differ-
entiation and is thus a high-pass filter. LEAD_LAG combined can cause the output phase
to lag input at low frequency, and to lead input at high frequency, and can thus be used as
a band-pass filter.
Parameters
Parameter Declaration Data Type Memory Area Description
EN Input BOOL I, Q, M, D, L Enable input with signal state of 1 activates
the box
ENO Output BOOL I, Q, M, D, L Enable output has a signal state of 1 if the
function block is executed without error
IN Input REAL I, Q, M, D, L, P, con-
stant
The input value of the current sample period
to be processed
SAMPLE_T Output INT I, Q, M, D, L, P, con-
stant
Sample time
OUT Output REAL I, Q, M, D, L, P, con-
stant
The result of the LEAD_LAG operation
ERR_CODE Output WORD I, Q, M, D, L, P Returns a value of W#16#0000 if the
instruction executes without error; see Error
Information for values other than
W#16#0000
LD_TIME Static REAL I, Q, M, D, L, P, con-
stant
Lead time in minutes
LG_TIME Static REAL I, Q, M, D, L, P, con-
stant
Lag time in minutes
GAIN Static REAL I, Q, M, D, L, P, con-
stant
Gain as % / % (the ratio of the change in
output to the change in input as a steady
state).
Block library "Standard"
Description
VIPA SPEED7
Standard
Converting > FB 80 - LEAD_LAG - Lead/Lag Algorithm
HB00 | OPL_SP7 | Operation list | en | 18-30 795
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