Comtrol Modbus TCP User Guide - Manual (Page 39)

DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I Chapter 3. Embedded Configuration Pages- 39
Serial Port Packet ID Settings (Raw-Data Only)
3.3.5. Serial Port Packet ID Settings (Raw-Data Only)
Use the Serial Port Packet ID Settings (Raw-Data Only) area of the Edit Serial Configuration page to
configure the raw data serial port packet identification (ID) settings for a serial port.
Serial Port Packet ID Settings (Raw-Data Only)
STX (Start of
Transmission)
Rx Detect
When enabled, the DeviceMaster UP detects an STX (start of transmission) byte
sequence which is configured as one byte or two bytes when it receives a serial packet.
The length indicates the number of STX bytes, valid values for length are:
• none - Disables this function and the DeviceMaster UP accepts the first byte received
after the last ETX byte(s) as the start of the next data packet.
• one byte - Scans serial data for one STX byte and when the DeviceMaster UP finds
an STX byte it collects the data. If the first byte is not the STX byte, it discards the
byte. The DeviceMaster UP continues to discard the bytes until it finds an STX byte.
• two bytes - Scans serial data for two STX bytes and when the DeviceMaster UP finds
two STX bytes it collects the data. If the STX bytes cannot be found, it discards the
bytes. The DeviceMaster UP continues to discard the bytes until it finds the two STX
bytes.
Byte 1 - Specifies the character that represents the first STX byte. The DeviceMaster UP
looks for this character in the first STX byte, if the length is one byte or two bytes. You can
specify a value between 0 and 255 in decimal format.
Byte 2 - Specifies the character that represents the second STX byte. The DeviceMaster
UP looks for this character in the second STX byte, only if the length is two bytes. You
can specify a value between 0 and 255 in decimal format.
ETX (End of
Transmission)
Rx Detect
When enabled, the DeviceMaster UP detects an ETX (end of transmission) byte
sequence that is configured as one byte or two bytes marking the end of the serial packet.
The length indicates the number of ETX bytes, valid values for length are:
• none - Disables this function and the DeviceMaster UP uses the Rx Timeout Between
Packets to indicate the end of data packet.
• one byte - Scans serial data for one ETX byte and when the DeviceMaster UP finds
the ETX byte, it identifies the data as a serial packet.
• two bytes - Scans serial data for two ETX bytes and when the DeviceMaster UP finds
the ETX bytes, it identifies the data as a serial packet.
Byte 1 - Specifies the character to scan for in the first ETX byte, if the length is one byte
or two bytes. You can specify a value between 0 and 255 in decimal format.
Byte 2 - Specifies the character to scan for in the second ETX byte, if the length is two
bytes. You can specify a value between 0 and 255 in decimal format.