Rockwell Automation 1734-485ASC POINT I/O ASCII User Manual - Manual (Page 24)

Publication 1734-UM009B-EN-P - July 2003
1-14 Installing the ASCII Module
Operating Mode Selections The ASCII module has several different operating modes, some of
which are available only in certain combinations. Major options are
summarized below, with additional details provided in chapter 2.
Transmit Handshake vs. Transmit Immediate Option
This option defines when the ASCII module transmits data out of its
serial port.
With Transmit Handshake active (default), the ASCII modules keys
on the second byte (TX Transaction ID) of the poll command or
explicit message to determine whether or not the consumed data from
the DeviceNet Master is to be transmitted out the serial port. While
this TX ID is static, the module will not transmit the command data.
Upon sensing a change in value of the TX ID byte, the module
transmits the data. It will initiate one serial transmission for each
change in the TX ID value, regardless of the data string value.
In Transmit Immediate mode, the ASCII module ignores the TX ID
byte value and initiates a new serial port transmission with each
message received from DeviceNet.
These actions take place with either a Poll command or an explicit
message that writes to the consume assembly object or the serial port
object.
TIP
Care should be taken when selecting this option for
I/O messaging. See page 2-24 for details.