Chapter 6. Serial Communications
90
DigitalFlow™ DF868 Multipurpose Ultrasonic Liquid Flowmeter Programming Manual (2-Channel)
6.5.2 Point-To-Point Wiring
Standard factory wiring of the RS485 serial interface is configured for point-to-point wiring. That is, a single Model
DF868 may be wired directly to a single personal computer. To connect the RS485 serial interface, refer to Figure 8 on
page 89 and complete the following steps:
Note:
For compliance with the European Union’s Low Voltage Directive (73/23/EEC), a transparent plastic shroud
protects the electrical connections. The shroud must remain in place, except while wiring the unit. Reinstall
the shroud after the wiring has been completed.
1.
Disconnect the
main power
to the electronics console and open the cover.
WARNING!
Dangerous voltages exist within the electronics console. Do not perform any wiring operations until
the main power to the unit has been disconnected.
2.
Remove the clear plastic
shroud
that covers the electrical connectors.
3.
Using a
twisted-wire pair
, connect the XMT+ terminal of the barrier strip to the T+/R+ terminal of the PC’s RS485
adapter and connect the XMT– terminal of the barrier strip to the T-/R- terminal of the PC’s RS485 adapter (see
the documentation provided with the RS485 adapter for details).
Note:
The XMT+ terminal on the barrier strip is the screw opposite the red wire connection and the XMT– terminal
on the barrier strip is the screw opposite the green wire connection.
4.
Reinstall the clear plastic shroud, close the cover to the electronics console and reconnect the main power.
The RS485 serial interface is now ready for point-to-point operation.
IMPORTANT:
The installed version of the Model DF868 software must be Version F2Z or higher to support RS485
operation. If necessary, contact the factory for information about a software upgrade.