Advantech UNO-2160, User Manual

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11 Chapter 2
2.3.6 RS-485 Auto Flow Control Mode and RS-422 Mas-
ter/Slave Mode Selection
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 Control and RS-422 Slave/Master Selection
SW3 DIP Switch Setting COM Port Mode Selections
COM3
RS-422: Slave mode
RS-485: Auto flow control
COM4
RS-422: Slave mode
RS-485: Auto flow control
COM3
RS-422: Master mode
RS-485: N/A
COM4
RS-422: Slave mode
RS-485: Auto flow control
COM3
RS-422: Slave mode
RS-485: Auto flow control
COM4
RS-422: Master mode
RS-485: N/A
COM3
RS-422: Master mode
RS-485: N/A
COM4
RS-422: Master mode
RS-485: N/A
1
2
O
N
1
2
O
N
1
2
O
N
1
2
O
N