Functional Substitutions

This table documents the recommended substitutions of IEC 61499-style function block types for those IEC 61131-3 function block types and functions that are no longer supported by the Functional Programming pattern for programming in the IEC 61131-3 FBD language.
Unsupported IEC 61131-3
Function Block Type
Recommended IEC 61499
Function Block Type
CTD E_CTD
CTU E_CTU
CTUD E_CTUD
CTUD E_CTUD
F_TRIG E_F_TRIG
R_TRIG E_R_TRIG
RS E_RS
SR E_SR

In the table below, the notation xxx represents a supported data type, e.g., REAL.

Unsupported
IEC 61131-3 Function
Recommended IEC 61499
Function Block Type
DATE_AND_TIME functions,
e.g., MAX_DATE_AND_TIME
FB_xxx_DT,
e.g., FB_MAX_DT
GE, GT, LE, LT, LIMIT, MIN, MAX
for bit strings
Not supported for
BOOL, BYTE, WORD, DWORD, LWORD
DIV_xxx FB_DIV_xxx
MOD_xxx FB_MOD_xxx
ROL_xxx FB_ROL_xxx
ROR_xxx FB_ROR_xxx
SINT operations Not supported
WSTRING functions (CONCAT, etc.) FB_CONCAT, etc.

Last updated:  2006-09-14.
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