Rockwell Automation 20-COMM-K CANopen Adapter - Manual (Page 116)

G-8 Glossary
20-COMM-K CANopen Adapter User Manual
Publication 20COMM-UM012B-EN-P
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, Reference, and Datalink
data. If the drive was running and using the Reference from the adapter, it
will stay running but at zero Reference.