15 StandardThe block library can be found for download in the ‘Service/Support’ area ofwww.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 youhave to import them into your project.Ä Chap. 5 ‘Include VIPA library’ page 6915.1 Converting15.1.1 FB 80 - LEAD_LAG - Lead/Lag AlgorithmThe Lead/Lag Algorithm LEAD_LAG function block allows signal processing to be doneon 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 greaterthan zero. The LEAD_LAG algorithm uses the following equation:Typically, LEAD_LAG is used in conjunction with loops as a compensator in dynamicfeed-forward control. LEAD_LAG consists of two parts. Phase lead shifts the phase of thefunction block’s output so that it leads the input whereas phase lag shifts the output sothat it lags the input. Because the lag operation is equivalent to an integration, it can beused 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 phaseto lag input at low frequency, and to lead input at high frequency, and can thus be used asa band-pass filter.ParametersParameter Declaration Data Type Memory Area DescriptionEN Input BOOL I, Q, M, D, L Enable input with signal state of 1 activatesthe boxENO Output BOOL I, Q, M, D, L Enable output has a signal state of 1 if thefunction block is executed without errorIN Input REAL I, Q, M, D, L, P, con-stantThe input value of the current sample periodto be processedSAMPLE_T Output INT I, Q, M, D, L, P, con-stantSample timeOUT Output REAL I, Q, M, D, L, P, con-stantThe result of the LEAD_LAG operationERR_CODE Output WORD I, Q, M, D, L, P Returns a value of W#16#0000 if theinstruction executes without error; see ErrorInformation for values other thanW#16#0000LD_TIME Static REAL I, Q, M, D, L, P, con-stantLead time in minutesLG_TIME Static REAL I, Q, M, D, L, P, con-stantLag time in minutesGAIN Static REAL I, Q, M, D, L, P, con-stantGain as % / % (the ratio of the change inoutput to the change in input as a steadystate).Block library "Standard"DescriptionVIPA SPEED7 StandardConverting > FB 80 - LEAD_LAG - Lead/Lag AlgorithmHB00 | OPL_SP7 | Operation list | en | 18-30 795
