
Chapter 3 _______________________________________________________________ Installation
VAISALA _______________________________________________________________________ 53
RS-422/485 Interface
0605-033
Figure 33
RS-485 Module
Numbers refer to Figure 33 above:
1
=
Flat cable pins
2 = Selection
switches
3
=
Screw terminals for wiring
NOTE
The markings on the module and in this manual are according to the line
driver manufacturers’ application notes, where A is posive against B
when measured with a voltmeter.
When connecting the module, be prepared to swap the A and B wires if
you have a communication problem.
Installation and Wiring
1.
Disconnect the power. In case the RS-485-module is installed in
the factory, continue with the item 4.
2.
To attach the module, open the transmitter cover and fasten the RS-
485 module to the bottom of the housing with four screws.
3.
Connect the flat cable between the RS-485 module and the
motherboard's pins
MODULE1 (Communications).
4.
Pull the network wirings through the cable gland.
5.
Connect the twisted pair wires (1 or 2 pairs) to the screw terminals
as presented in Table 6: