PLC-API Description of the transfer behavior: The internal calculation is performed in each sampling step according to the second standard form, for which the following block diagram applies: The transfer function can be brought into the form shown in the block diagram by means of some transformations: Fig. 1: FB_CTRL_TRANSFERFUNCTION_2_G2 The coefficients of the numerator polynomial are calculated according to the following rule: Fig. 2: FB_CTRL_TRANSFERFUNCTION_2_bi The programmer must create the following arrays in the PLC if this function block is to be used: ar_fNumeratorArray : ARRAY[0..nOrderOfTheTransferfunction] OF FLOAT; ar_DenominatorArray :
ARRAY[0..nOrderOfTheTransferfunction] OF FLOAT; ar_stTransferfunction2Data : ARRAY[0..nOrderOfTheTransferfunction] OF ST_CTRL_TRANSFERFUNCTION_2_DATA; The coefficients b 0 to b n are stored in the array ar_fNumeratorArray. This must be organized as follows: ar_fNumeratorArray[ 0 ] := b0; ar_fNumeratorArray[ 1 ] := b1; ... ar_fNumeratorArray[ n-1 ] := bn-1; ar_fNumeratorArray[ n ] := bn; The coefficients a 0 to a n are stored in the array ar_DenominatorArray. This must be organized as follows: ar_DenominatorArray [ 0 ] := a0; ar_DenominatorArray [ 1 ] := a1; ... ar_DenominatorArray [ n-1 ] := an-1; ar_DenomiantorArray [ n ] := an; TS4100 36 Version: 1.1