Rockwell Automation Logix5000 Controllers Add-on Instructions Programming Manual - Manual (Page 78)

Chapter 3 Using Add-On Instructions
5. Define arguments for each Parameter on the instruction call.
The instruction appears as follows in each of the languages.
Ladder Diagram:
Parameter With Description
Single question mark This is a required InOut parameter. Enter a tag.
Single and double question marks This is a required Input or Output parameter. Enter a tag.
Double question marks
This is not a required parameter. You can either:
• Leave as is and use the default value.
• Enter a different value if it’s an Input parameter.
Function Block Diagram:
Item Description
Nub on the end of pin
This is a required Input or Output parameter.
You must wire the pin to an IREF, OREF, connector, or another
block to verify.
Single question mark This is a required InOut parameter. Enter a tag.
No nub on the end of pin
This is not a required parameter.
You can either:
• Leave as is and use the default value.
• Enter a different value if it’s an Input parameter.
78 Rockwell Automation Publication 1756-PM010F-EN-P - October 2014