Rockwell Automation 1757-PROCESSLINX ProcessLinx OPC Server to Server Software User Manual - Manual (Page 37)

Publication 1757-UM002B-EN-P - January 2003
ProcessLinx TagMap Configuration 3-17
under the function blocks. Note: Some of the items are not connectable.
Data Conversion/Scaling Most analog values exchanged between the ProcessLogix OPC Server
and an External OPC Server are already expressed in engineering units
and therefore, linear scaling of analog values is not required. To
accommodate discrete values not meeting this condition, TagMap
definitions allow scaling.
OPC Items ProcessLogix OPC Items are accessed from one of four point
types/categories: Status points, Analog points, Accumulator points and
Control Processor points. The ProcessLogix OPC data item addressing
is:
Simple Points
Simple Points are those other than Control Processor points.
• point.parameter [/enum]
Control Processor Points
• point.block.parameter [/enum]
Some OPC Servers do not support string value writes from OPC
Clients, such as ProcessLinx. The “/enum” designation should be used
carefully.
Table 3.E Data Addressing Terminology
Term Description
point point ID
parameter point parameter name listed in “Point Parameter Data
Addressing” section in Knowledge Builder.
Navigate to Knowledge Builder
⇒
Server and Client
Configuration Guide
⇒
Using ProcessLogix Data in Other
Applications
⇒
ProcessLogix OPC Support.
block control module parameter for Control Processor Points.
/enum – specifies whether the parameter should be treated as an
enumerated type. Defining this after the Item name returns
the string enumerated value for the point (i.e. MAN or AUTO
for a controller mode point).