Serial packet identification – Comtrol UP DeviceMaster User Guide User Manual
Page 69
DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I
Chapter 3. Embedded Configuration Pages- 69
Serial Packet Identification
3.3.3. Serial Packet Identification
Use the Serial Packet Identification area of the Edit Serial Configuration page to configure the raw data
serial port packet identification (ID) settings for a serial port.
For more information on serial packet ID settings, see
2.3.1. Serial Port Configuration Object Definition (70
Rx Timeout
Between
Packets
Specifies the following information, once the start of a packet is received:
•
How long the DeviceMaster UP should wait (in milliseconds) before timing-out,
if the ETX Rx Detect length is one byte or two bytes and the ETX byte(s) are not
received.
•
The time to wait in milliseconds between serial packets if the ETX Rx Detect
length is set to none.
Serial Port Packet Identification
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.
Serial Configuration (Continued)