Rockwell Automation 20-COMM-P Profibus Adapter - Manual (Page 110)

Glossary-6
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 command data. If the
drive was running and using the Reference from the adapter, it will stay
running but at zero Reference.
20COMM-UM006A-EN-P.book Page 6 Friday, September 28, 2001 10:43 AM