Discrete I/O (Relay) Connections - Mettler Toledo IND131 Guia De Instalacion

COM2/Discrete I/O (Solid State) option board is shown in Figure 2-50. The COM2 port is positioned
to the far left side of the board.
The COM2 port includes connections for RS-232 and RS-485. Table 2-9 indicates which terminal
is which signal on the COM2 port. The type of interface used must be selected in the setup of
COM2.
For an example of connecting an external RS-232 device to the COM2 serial port, refer to Figure
2-41, as RS-232 connections are similar for COM1 and COM2. An example of connecting an RS-
485 device is shown in Figure 2-44.
2.4.5.2.

Discrete I/O (Relay) Connections

The relay output version of the COM2/Discrete I/O option board (Figure 2-45) provides two isolated
inputs and four dry-contact normally open relay outputs. The inputs can be selected as either active
or passive based on the position of the slide switch on the board.
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Table 2-9: COM2 Connections
Terminal
Figure 2-44: RS-485 Wiring to COM2
THE INTERNAL DISCRETE I/O RELAY OPTION (#72225753 OR #72225757) MUST NOT BE
USED IN A TERMINAL INSTALLED IN AN AREA CLASSIFIED AS DIVISION 2 OR ZONE 2/22.
FAILURE TO COMPLY WITH THIS WARNING COULD RESULT IN BODILY HARM AND/OR
PROPERTY DAMAGE.
METTLER TOLEDO IND131/IND131x/IND331/IND331xx Installation Manual
Signal
TxD Transmit RS-232
RxD Receive RS-232
Gnd Logic Ground
Tx+ A Transmit + RS-485
Tx- B Transmit - RS-485
NOTES:
1. USE ONLY SHIELDED CABLE.
2. MAXIMUM CABLE LENGTH: 1000 FEET (304 METERS).
3. WIRE SIZE: 18 AWG (0.8 mm
2
24 AWG (0.2 mm ) MINIMUM.
WARNING
2
) MAXIMUM
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