Vaisala MMT330 - Manual (Page 57)

Chapter 3 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 57
1102-023
Figure 33 RS-422/485 Module
The following numbers refer to Figure 33:
1 = Flat cable pins
2 = Selection switches
3 = Screw terminals for wiring
NOTE The data lines on earlier versions of the RS-422/485 module are marked
A and B instead of D1+ and D0-. When the line is idle, D1+ has positive
voltage compared to D0-.
When connecting the module, be prepared to swap the D1+ and D0-
wires if you have a communication problem.
Installation and Wiring
1. Disconnect the power. In case the RS-422/485 module is installed
in the factory, continue with the item 4.
2. To attach the module, open the transmitter cover and fasten the RS-
422/485 module to the bottom of the housing with four screws.
3. Connect the flat cable between the RS-422/485 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 5 on page 58:
1
2
3