Vaisala Hydromet Data Collection Platform - Manual (Page 343)

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
B.
3-4
X6 1-2
X5 1-2 The line terminating resistor is in use with RS-
485.