Vaisala Hydromet Data Collection Platform - Manual (Page 31)

Chapter 2 __________________________________________________________ Product Overview
VAISALA_______________________________________________________________________ 29
The RS-485 isolated communication module provides a 2-wire or 4-
wire RS-485-communication link between two devices with a similar
interface. This module is used, for example, for connecting displays and
terminals to the data logger when the distance is longer than 15 meters.
The maximum distance for the isolated RS-485 module is
approximately 1500 meters at full speed. The module must be
configured before use.
Dual-Isolated RS-485 Communication Module
0906-070 Figure 10 Dual-Isolated RS-485 Communication Module
DSI486
The RS-485 dual communication module is dual-isolated and can be
used in the RS-232, RS-485, or SDI-12 mode. The communication
mode is selected by the correct wiring of the I/O pins and with the
correct jumper settings on the board. The dual RS-485 communication
module is used, for example, for connecting displays, terminals, and the
data logger together when the distance is longer than 15 meters. The
maximum distance is approximately 1500 meters at full speed. The
module must be configured before use.
The RS-485/422 channels A and B are galvanically isolated from the
host board's electronics. The +5 VDC power supplies of channels A and
B are also isolated from each other with capacitors. Thus, it is possible
to wire these two channels to separate locations.
The RS-232 mode utilizes channel B. When channel B is used in the
RS-232 mode, it is possible to use channel A as a galvanically isolated
two-wire RS-485 channel. The RS-232 channel is galvanically
connected to the host board's GND potential.