Rockwell Automation 1799-DASCII DeviceNet Serial Interface - Manual (Page 30)

30 DeviceNet Serial Interface Module
Publication 1799-IN012B-EN-P - July 2008
Transmit Serial Data to the ASCII Device
Read this section for information about transmitting serial data to the ASCII device.
Set Up the Transmit-character Buffer Length (parameter 19)
The Transmit-character buffer length is the number of characters that the
1799-DASCII module can receive in its transmit buffer from the DeviceNet system.
This size contributes to the I/O's Consume Size. This size can be found in the
Parameter object.
Set Up and Use the Transmit Delimiter (parameters 20 and 21)
The transmit delimiter is an end-of-string character that is used by the 1799-DASCII
module to determine how many bytes to transmit over the serial link to the
1799-DASCII device. This transmit delimiter is used if the Transmit Buffer Length
equals 0. If the buffer length is not 0, the 1799-DASCII module ignores the transmit
delimiter.
The 1799-DASCII module transmits up to and including the delimiter when the
above condition is met. The transmit delimiter can be set to any valid I/O character
that can be received over the link (parameter 21). Be careful not to set the
delimiter to a value outside of the valid range for the number of data bits. (Note
that a data bit size setting of 7 lets a delimiter range of 0…127 dec., 00…7Fhex). If
the delimiter is not valid, or the delimiter is never received, the device updates the
output buffer on detection of a buffer filled condition. These values can be set and
retrieved by using the standard set/get services in the Transmit Record Class 0x71.