Mettler Toledo IND231 Manual De Instalación página 37

2.4.7.1. COM2 with Isolated RS-232/422/485 Option
The COM2 with RS-232/422/485 option board (Figure 2-31) provides a single isolated serial port.
The COM2 port provides RS-232, RS-422and RS-485 connections. The hardware connection must
be configured in the Communication section of the setup menu structure – refer to Chapter 3 of the
User's Guide, Configuration. Figure 2-33 and Table 2-6 show the connection details.
The jumpers on the board (W1 and W2, indicated in Figure 2-31) are open by default. They enable
the connection of a 120 ohm terminal resistor to the RS-422 and RS-485 A/B signals. If it is
necessary to enable the terminal resistor, short the jumpers as shown in Figure 2-32.
30094803 | 00 | 08/2013
Connector to
Main board
Connector for
RS-422 and
RS-485
Figure 2-31: COM2 with RS-232/422/485
Figure 2-32: COM2 Jumper Positions
Figure 2-33: COM2 Port Signals
Table 2-6: Isolated Serial Port Pin Assignments
Terminal Signals
Pin 1 TX/RX+
Pin 2 TX/RX-
Pin 3 RX+
METTLER TOLEDO IND231/IND236 Installation Manual
NOTES:
1. RS-232: MAXIMUM CABLE LENGTH: 50 FEET (15
METERS)
2. RS-422/485: MAXIMUM CABLE LENGTH: 1000 FEET
(304 METERS)
3. WIRE SIZE: 18 AWG (0.832 mm
24 AWG (0.205 mm
Description
RS-485 data A or RS-422 Transmit data A
RS-485 data B or RS-422 Transmit data B
RS-422 Receive data A
Jumpers for RS-
422/485 terminal
resistor
RS-232 Connector
2
) MAXIMUM
2
) MINIMUM
2-17