Vaisala AWS330 - Manual (Page 242)

User's Guide ______________________________________________________________________
240 _________________________________________________________________ M211296EN-B
Communication Modules
The communication modules are housed inside the QML logger.
Dual RS-485 Module DSI486
0906-070
Figure 126 Dual-Isolated RS-485 Communication Module DSI486
Data 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, channel A can either transmit or receive, depending on the
configuration.
Jumper X4 defines the line terminating resistor for channel A. Remove
jumper X4 if you do not need the terminating resistor of the dual RS-485
module. Figure 127 below provides a schematic wiring diagram for dual
RS-485.
1006-101
Figure 127 Dual RS-485 Module Wiring Diagram
Data 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, channel B can either transmit or receive,
depending on the configuration.