4.1.1   IO Tags

An IO Tag describes a single parameter from the field device. A single register in a PLC is the most common use for an analog parameter (e.g. a counter). Often a single-bit is defined as a single point using a digital or discrete parameter (e.g. run/stop status for a limit switch). A single field measurement for an indication-only point is usually a tag (e.g. the flow measurement from an indication-only loop with a tagname FI1001).

A Tag has other features assigned to it by WebAccess, for example description, alarms, access level, output limits etc. All WebAccess tags are multi-dimensional, but a tag starts with a single piece of information from the field device.

The software license control file on the SCADA node limits the number of IO tags.  Each IO tag counts as one.