Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 67)

Choosing Module Features
Chapter 3
3Ć25
The transmission mode that you choose is determined by the
specifications of your ASCII device and the requirements of your
application (Table 2.L).
Table 2.L
Mode of Transmission
If Your
ASCII Device Is And Your Application Requires Then Select Using Code
Full Duplex That your ASCII device displays data sent to the ASCII module
That no data is displayed
Full Duplex with Echo
Full Duplex without
Echo
000
001
Simplex Read Only the transmission of data from your ASCII device Simplex Read or Full
Duplex
010
Simplex Write Only the display of data received by your ASCII device Simplex Write or Full
Duplex
011
Half Duplex That your ASCII device displays data sent to the ASCII module
That no data is displayed
Half Duplex with Echo
Half Duplex without
Echo
100
101
Record the mode of transmission selection by writing the 3-digit code in
IW1(05-07). Use the form (found at the end of this chapter) or the boxes
below.
IW1
Mode
Transmission
07 06 05
Choose single transfer when you want the module to send a single string
to the processor in each block transfer, or when the string is long enough
to require more than one block transfer.
Choose multiple transfers when your ASCII device transmits short strings
(31 characters per string or less) at a high rate of transmission. Then the
module will include more than one string in each block transfer. The
highest number of strings that you can transfer in one block transfer is the
number of complete strings that the module can load into 62 (or fewer)
block transfer words.
Choosing Transmission Mode,
IW1(05Ć07)
Choosing Single or Multiple
Transfers, IW2(17)