User Guide

30
CONNECTIONS
The connections for the 6-pin RS485 terminal provided (#1
on page 7) are as follows:
There is an internal short between the two A pins and be-
tween the two B pins.
The instrument has no internal line termination. To terminate
the line, an external resistor equal to the characteristic line
impedance (typically 120Ω) must be added at both ends of
the line.
Up to 32 units can be connected to the same RS485 line,
with a total line length of up to 1.2 Km using 24AWG cable.
To minimize electromagnetic interferences, use shielded or
twisted pair cable to connect the units.
Each unit is identified by its process ID number (setup item
“01”).
The controller acts as a “slave” device: it only answers to
commands received from a “master” device (e.g. an indus-
trial PC) connected to the line.