Rockwell Automation 2071-Axx Kinetix 3 Component Servo Drive Serial Host Command Reference Manual - Manual (Page 29)

Rockwell Automation Publication 2071-RM001B-EN-P - April 2013 29
Chapter
2
Communication Protocol (RS-232/ASCII)
Introduction The drive command protocol is a client-server protocol. A host computer is the
server, and each drive is a client. This chapter provides details about the Special
Symbols, Packet Structure, and Checksum in the serial communication protocol.
Special Symbols Special symbols used in the host commands include the following.
Packet Structure The packet structure is shown below.
Some simple commands might not have the Data field (for example, 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 .
If the drive receives the command without a communication error, the response is
in the same format as the host command. Numeric parameters are encoded as
strings.
Symbol Value Description
STX 0x02 Start of text
ETX 0x03 End of text
ACK 0x06 Acknowledged
BEL 0x07 Acknowledge alarm
NAK 0x15 Not acknowledged
CAN 0x18 Cancellation of command (For example, the drive sends CAN if the drive is already enabled,
but the JOG ON is requested.)
ETB 0x17 End of block
GS 0x1D Cannot save parameter
RS 0x1E Range over
US 0x1F Undefined
Start ID Host/
Response Command Data Separator Checksum End
Symbol STX dd # or $ SET or… d …d : c c ETX
Bytes 1 2 1 3 0 - n 1 1 1