Rockwell Automation 1799-DASCII DeviceNet Serial Interface - Manual (Page 21)

DeviceNet Serial Interface Module 21
Publication 1799-IN012B-EN-P - July 2008
Receive Serial Data from the ASCII Device
The 1799-DASCII module receives a number of characters at its serial port and
transmits these to the DeviceNet master (produces on the DeviceNet network) via
the following:
•
Polled I/O
•
Change-of-state (COS)
•
Cyclic
•
Explicit Message
The received character string is captured when one of the following occurs:
•
The specific number of bytes defined (max number of Receive characters) is received.
•
The defined End-of-String Terminator character is detected.
•
The specified non-zero time-out value (Message Time-out) is reached.
When any of these events occur, the 1799-DASCII module stores the received
message string in its internal buffer and transmits (produces) it onto the DeviceNet
network at the next opportunity.
Set Up the Receive-character Buffer Length (parameter 4)
The receive character buffer length is the number of characters that the
1799-DASCII module can receive from the serial device into its buffer at one time.
The length of the data string sent to the DeviceNet master is less than or equal to
this size, plus a 4-byte header.
When the 1799-DASCII module receives the character that fills the buffer, it sets the
nondelimited RECORD status flag and forces the data in the receive buffer to be