User Manual

Chapter 7 ____________________________________________________________ Technical Data

VAISALA______________________________________________________________________ 341

Dual RS-485 Module DSI486, Version A

Channel A is always used in the RS-485 mode. In 2-wire RS-485, both

transmitted and received data is sent via this channel. In 4-wire RS-485

this channel can either transmit or receive depending on the

configuration. Jumper X4 defines the line terminating resistor for the

data channel A. Remove the jumper X4 if you do not need the

terminating resistor of the dual RS-485 module. Figure 175 on page 341

provides a schematic wiring diagram for dual RS-485.

1006-101

Figure 175 Dual RS-485 Module Wiring Diagram

Channel B can be used either in the RS-485 mode or in the RS-232

mode. In 2-wire RS-485, both transmitted and received data is sent via

this channel. In 4-wire RS-485, this channel can either transmit or

receive depending on the configuration.

Figure 175 on page 341 provides a schematic wiring diagram for the

dual RS-485 connection, the dual 2-wire connection utilizing both

channels. The correct jumper settings for the channel B are listed in

Table 75 on page 341. The jumpers are located on the module as

illustrated in Figure 176 on page 342.

Table 75 Jumper Settings for Channel B in the RS-485 Mode

Jumper Connected

Pins

Function

X3 1-2 Sets the RS-485 mode active for the channel

3-4

X6 1-2

X5 1-2 The line terminating resistor is in use with RS-

485.