Function Block Responses to Overflow Conditions
In general, the function block instructions that maintain history do not update history with 
NAN, or 
INF values when an overflow occurs. Each instruction has one of these responses to an overflow condition.
NAN, or INF values when an overflow occurs. Each instruction has one of these responses to an overflow condition.Response | Instruction |
Response 1 Blocks execute their algorithm and check the result for NAN or INF. If NAN or INF, the block outputsNAN or INF. | ALM NTCH DEDT PMUL DERV POSP ESEL RLIM FGEN RMPS HPF SCRV LDL2 SEL LDLG SNEG LPF SRTP MAVE SSUM MAXC TOT MINC UPDN MSTD MUX |
Response 2
Blocks with output limiting execute their algorithm and check the result for NAN or INF. The output limits are defined by the HighLimit and LowLimit input parameters. If INF, the block outputs a limited result. If NAN, the output limits are not used and the block outputs NAN. | HLL, INTG, PI, PIDE, SCL, SOC |
Response 3
The overflow condition does not apply. These instructions typically have a boolean output. | BAND, BNOT, BOR, BXOR, CUTD, D2SD, D3SD, DFF, JKFF, OSFI, OSRI, RESD, RTOR, SETD, TOFR, TONR |
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