Rockwell Automation 22-COMM-P PowerFlex Profibus Adapter - Manual (Page 109)

Glossary-5
Feedback is used to monitor the speed of a drive. It consists of one 16-bit
word of input from the adapter to the network.
S Scanner
A scanner is a separate module (of a multi-module controller) or a
built-in component (of a single-module controller) that provides
communication with adapters connected to a network. See also
Controller.
A Scanner is often called Master.
Status Indicators
Status indicators are LEDs that are used to report the status of the
adapter, network, and drive. They are on the adapter and can be viewed
on the front cover of the drive when the drive is powered.
Z Zero Data
When communications are disrupted (for example, a cable is
disconnected), the adapter and drive can respond with zero data. Zero
data results in the drive receiving zero as values for Logic Command and
Reference data. If the drive was running and using the Reference from
the adapter, it will stay running but at zero Reference.