Rockwell Automation 1769-SM1 Compact I/O to DPI/SCANport Module - Manual (Page 168)

G-6 Glossary
SCANport Product
A device that uses the SCANport communications interface to
communicate with one or more peripheral devices. For example, a motor
drive such as a 1336 PLUS II is a SCANport product. In this manual, a
SCANport product is also referred to as “drive” or “host.”
Status Indicators
Status indicators are LEDs that are used to report the status of the
1769-SM1 module, drive(s), and network. They are on the 1769-SM1
module and are functional when a connected drive is powered.
T
Type 0/Type 1/Type 2 Control
When transmitting I/O, the module can use different types of messages
for control. The Type 0, Type 1, and Type 2 events help Allen-Bradley
personnel identify the type of messages that an module is using.
Z
Zero Data
When communications are disrupted (for example, a cable is
disconnected), the 1769-SM1 module and connected drive(s) can
respond with zero data. Zero data results in the drive(s) receiving zero as
values for Logic Command and Reference data. If the drive(s) was
running and using the Reference from the 1769-SM1 module, it will stay
running but at zero Reference.