Rockwell Automation 2092-DAx Ultra1500 Host Commands for Serial Communication Reference Manual - Manual (Page 11)

1 Publication 2092-RM001A-EN-P — March 2005
Chapter
1
Communications Protocol
Introduction The drive command protocol is a master - slave protocol. The host computer
is the master and the drive is the slave. This chapter provides details about the
Special Symbols, Packet Structure, and Checksum for the Ultra serial
communications protocol.
Special Symbols Special symbols used in the host commands include:
Packet Structure The packet structure is shown below:
Some simple commands might not have the Data field (e.g., Fault Reset).
Maximum packet size is 400 bytes. Each letter and digit in Command and Data
fields represents a single ASCII character.
All commands begin with an STX, and terminate with an ETX.
Symbol Value Description
STX 0x02 Start of Transmission
ETX 0x03 End of Transmission
ACK 0x06 Command Acknowledged
GS 0x29 Cannot change the value of the parameter while drive is enabled.
RS 0x30 Value is out of range
US 0x31 Invalid command
NAK 0x15 Communication Error (Checksum Error)
Start ID Host/
Response
Command Data Separator Checksum End
symbol STX dd # / $ SET or… d … d : c c ETX
bytes 1 2 1 3 0 - n 1 1 1