When are user specified initialisation values for variables used?
User specified initial values apply to non-retentive variables both at “cold restart” and “warm restart”, but they only apply to retentive variables at “cold restart”. On “warm restart” retentive variables have the same values as existed when their resource stopped executing, e.g. due to a power outage. The 61131-3 amendment allows initialisation values defined by the VAR_CONFIG construct to override type specific initial values. Therefore, VAR_CONFIG specified initial values apply at “cold restart” or “warm restart” for non-retentive variables, and to “cold restart” for retentive variables. • Can function block instances be passed as inputs to other blocks? Yes if function block FB1 is passed as an input to a second function block FB2, it is possible to invoke the function block FB1 within the body of FB2. Any input parameters of FB1 not defined in the invocation call within FB2 will take values defined by earlier invocations of FB1 made outside of FB2. Function block instances should
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- When are user specified initialisation values for variables used?
