Rockwell Automation 1769-SM2 Compact I/O DSI/Modbus Communication Module - Manual (Page 46)

3-8 Configuring the Module
See Table 3.C for descriptions of these configuration words.
5. Click OK when finished. The MicroLogix 1500 will download the
configuration data to the 1769-SM2 module when the controller is
placed in run mode.
Special Case— Data Entry for 2 Stop Bits Communication
The Chan.1, Chan. 2, and Chan 3 tabs do not allow settings that specify 2
stop bits communication in Modbus RTU operation. For this type of
configuration, you must use the Generic Extra Data Config tab to enter
the data by performing these steps:
1. To configure a specific 1769-SM2 module channel for 2 stop bits
communication, click on the Generic Extra Data Config tab.
2. On the Generic Extra Data Config tab screen, enter the appropriate
values from Table 3.D in the offset addresses highlighted in Figure 3.6 .
Figure 3.6 Entering Data for 2 Stop Bits on Generic Extra Data Config Screen
Table 3.D Entry Data for 2 Stop Bits Communication
1769-SM2 CH Offset Address Value Description
1 10 3
4
5 Sets CH1 for 8-N-2 format
Sets CH1 for 8-E-2 format
Sets CH1 for 8-O-2 format
2 24 3
4
5 Sets CH2 for 8-N-2 format
Sets CH2 for 8-E-2 format
Sets CH2 for 8-O-2 format
3 38 3
4
5 Sets CH3 for 8-N-2 format
Sets CH3 for 8-E-2 format
Sets CH3 for 8-O-2 format