Why are FB parameters defined as register and not as constant?

FAQ #100033

Some of the parameters of the FB's for programming the H-Modules are defined as registers that have to be loaded before the call of the FB.


A constant can have a value up to 16383 (

14 bit). Unlike a constant, a register can hold a 31 bit value (signed). Since the values of the parameters can be up to 31 bits, it is required to use registers to hand over the parameters to the FB



PCD2 / Hxxx

PCD3 / Hxxx

PCD4 / Hxxx

Last update: 29.05.2015 07:17

First release: 08.06.2004 12:05

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