Rs-485 Auto Flow & Rs-422 Master/Slave Mode; Table 2.1:Auto Flow & Slave/Master Selection - Advantech UNO-2170 User Manual

2.3.6 RS-485 Auto Flow & RS-422 Master/Slave Mode
You can set the "Auto Flow Control" mode of RS-485 or "Master/Slave"
mode of RS-422 by using the SW3 DIP switch for each RS-422/485 port.
In RS-485, if the switch is set to "Auto", the driver automatically senses
the direction of the data flow and switches the direction of transmission.
No handshaking is necessary.
In RS-422, if DIP switch is set to "On," the driver is always enabled, and
always in high or low status.
Table 2.1: Auto Flow & Slave/Master Selection
SW3 DIP Switch Setting
1
2
1
2
1
2
1
2
COM Port
COM3
O
N
COM4
COM3
O
N
COM4
COM3
O
N
COM4
COM3
O
N
COM4
11
Mode Selections
RS-422: Slave mode
RS-485: Auto flow control
RS-422: Slave mode
RS-485: Auto flow control
RS-422: Master mode
RS-485: N/A
RS-422: Slave mode
RS-485: Auto flow control
RS-422: Slave mode
RS-485: Auto flow control
RS-422: Master mode
RS-485: N/A
RS-422: Master mode
RS-485: N/A
RS-422: Master mode
RS-485: N/A
Chapter 2