1-8
1
character sequence is an STX character (02) followed by the address
character. The address character is the ASCII number with a hex value of
30 - 3F. An example is the IDN query sent to a 2307 at address 4.
i.e.
STX 4 * I D N ? (LF)
Prompts are supported when network addressing is enabled. The transmitter
is enabled until the prompt is sent. SRM messages are inhibited when
Network Address is selected
1.5.8
RS-422/RS-485 Packet Protocol
When Network Packet protocol is enabled, the unit operates with serial
packets that contain the commands, queries and responses. The unit
responds to packets containing an address character that matches the
address set in the Flash memory. If the checksum and command is valid,
the command is executed and an ACK packet is returned. If the checksum
or command is invalid, a NAK response is returned. ACK/NAK command
response packets contain the current ESR Register value.
The general packet format is:
STX Addr Message Characters....ETX Checksum
An acknowledgment packet is:
ACK Addr ESR_Register_Value ETX Checksum
ACK Addr Query_response ETX Checksum
An NAK packet is:
NAK Addr ESR_Register_Value ETX Checksum
Where:
ASCII characters 0 to 1F hex are reserved for message control.
ASCII characters 20-7F are for address and data.
Address character is 30-3F hex.
STX is ASCII character 02 hex.
ETX is ASCII character 03 hex.
ACK is ASCII character 06 hex.
NAK is ASCII character 15 hex.
Checksum is the exclusive OR sum of all of the characters
from the STX character though the ETX character.
