Enable EN/ENO in ladder diagram instructions

The rung state in a ladder diagram (LD) diagram is always Boolean, and the first input and first output of an instruction are connected to the rung. For instructions that have EN inputs or ENO outputs, use the
Properties
 pane to enable or disable EN/ENO:
  • When enabled, the value of the EN input or ENO output parameter is shown on the bit lag.
  • When disabled, the value of the EN input or ENO output parameter is shown in the instruction box.
When EN/ENO is disabled:
  • Assign a variable to or enter the value for the EN input or ENO output parameter for instructions that have instances.
  • Assign a variable to or enter the value for EN input or ENO output parameters for instruction that do not have instances.
IMPORTANT:
  • A user-defined input parameter cannot be used to enable or disable user-defined functions (UDF) or user-defined function blocks (UDFB) because the input parameter only enables or disables the instructions inside the UDF or UDFB.
  • To enable or disable the running of a UDF or UDFB, select the
    EN/ENO
     checkbox using the
    Properties
     pane for the specified UDF or UDFB. For example, when
    EN/ENO
     is turned off, the UDFB does not execute and the output parameters are not overwritten.
To enable EN/ENO in ladder diagram instructions
  1. In the ladder diagram language editor, select an instruction block instance.
  2. In
    Properties
    , turn on
    EN/ENO
    .
    In some cases, enabling parameters are required for the instructions that execute on call. The following example shows an SUS instruction block with an
    Enable
     input.
    EN/ENO example
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