Rockwell Automation Logix5000 Controllers Add-on Instructions Programming Manual - Manual (Page 79)

Using Add-On Instructions Chapter 3
Structured Text:
The instruction expects arguments for required parameters as listed in the instruction
tooltip.
Tip: For help with an instruction, select the instruction and then press F1. In Structured Text, make sure the
cursor is in the blue instruction name.
A module reference parameter is an InOut parameter of the MODULE data type
that points to the Module Object of a hardware module. You can use module
reference parameters in both Add-on Instruction logic and program logic. Since
the module reference parameter is passed by reference, it can access and modify
attributes in a hardware module from an Add-On Instruction. Follow this
procedure to use a module reference parameter from within the Add-On
Instruction. This example shows how to retrieve the communication path for a
hardware module.
1. Create the module reference parameter in the Add-On Instruction. See
Creating a module reference parameter on page 42 .
2. Create a SINT tag in the Add-On Instruction to hold the module
communication path.
3. Add a GSV instruction in the Add-On Instruction, using the programming
language you chose for the Add-On Instruction. The GSV instruction
allows you to retrieve module information.
4. In the GSV instruction, choose the following values to retrieve the
communication path to the module.
Attribute Value
Class Name Module
Instance Name The module reference parameter you created in the Add-On Instruction
(IO_ModuleSts below)
Attribute Name Path. This is the communication path to the module.
Dest The tag to hold the module path (Module_Path below)
Referencing a hardware
module
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