GE AquaTrans AT868 User Manual page 20

Wiring an RS485 Interface
Using an INMAC Converter
Installation
Use the optional RS485 serial port to network multiple AT868 flow
transmitters to a single computer terminal. Upon request, the standard
RS232 port on the AT868 may be configured as a two-wire, half-
duplex RS485 interface, through a device such as the INMAC Model
800052 RS232-RS422/RS485 converter.
If the AT868 is configured at the factory for RS485 operation, the
INMAC converter is not necessary.
Refer to one of the following sections to wire the unit:
•
Using an INMAC Converter - see below.
•
Using a Factory-Configured Serial Interface - on page 1-12.
To wire the RS485 serial port, refer to Figure 1-4 on page 1-14 and
complete the following steps:
1. Follow the instructions on page 1-4 to prepare the unit before you
connect power.
2. Feed one end of the cable through the conduit hole and wire the
leads to the COMMUNICATION terminal block as shown in
Figure 1-4 on page 1-14. Secure the cable clamp.
3. Connect the other end of the cable to the converter (see
Figure 1-2 below).
!ATTENTION EUROPEAN CUSTOMERS!
To meet CE Mark requirements, all cables must be installed
as described in Appendix B, CE Mark Compliance.
4. If wiring of the unit has been completed, replace the plastic
shroud, reinstall the front cover on the enclosure and tighten the
screws.
Proceed to the next section to continue the initial wiring of the unit.
Model AT868
N.C. 5
N.C. 4
N.C. 3
RX 2
TX 1
Figure 1-2: Typical RS485 Connections
September 2004
Converter
1 TD OUT
2
3
4 RD IN
1-11