Scale Bases; Options; Isolated Serial Interface Rs232/Rs422/Rs485; Discrete I/O - Mettler Toledo IND231 Installationsanleitung

1.8.

Scale Bases

The IND231/IND236 terminal supports analog scale bases and provides 5 volts of excitation to
drive analog load cells. Up to four 350Ω load cells can be powered by the terminal.
A four- or six-wire load cell connection is provided, with sense lines to help maintain accuracy as
the load cell cable resistance changes due to variations in temperature.
1.9.

Options

Three kinds of option interface can be mounted on COM2. The connection pin specifications are
printed on the PCB.
The following options are available for the IND231 and IND236.
1.9.1.

Isolated Serial interface RS232/RS422/RS485

This optional port provides RS-232 and RS-422/485 communication which can be configured in
setup. The port is bidirectional and can be used for various functions such as print, auto print,
Toledo continuous output or SICS communications.
The COM2 port is galvanically isolated for both RS-232 and RS-485, to provide surge voltage
protection.
The RS-485 connection can be used as an RS-422 transmit only, when sending continuous output
to a scoreboard or remote display.
The interface RS422/485 is required for data transmission with higher baud rate over longer
distances up to 500 m.
Communication settings can be configured in the terminal setup menu.
1.9.2.

Discrete I/O

The discrete I/O interface option provides four dry-contact relay outputs. The relay contacts will
switch up to 30 volts DC or 250 volts AC at 1A.
The two inputs are switch selectable as either active (for simple pushbutton control) or passive (for
connection to devices that supply their own power for the inputs).
1.9.3.

USB

The USB port provided is a UART-USB device bridge acting as a virtual COM port, and is used for
communication of serial data to devices such as a PC. The port is bidirectional and can be
configured for various functions such as print, auto print, Toledo continuous output or SICS
communications. USB external keyboards and bar code scanners are not supported.
30094803 | 00 | 08/2013 METTLER TOLEDO IND231/IND236 Installation Manual 1-7