Rice Lake 320IS Plus Intrinsically Safe Digital Weight Indicator - I/O Module for Intrinsically Safe Systems Installation Manual - Manual (Page 7)

Installation 3
The I/O Module must be installed in a safe area. The
internal power supply unit provides DC voltage for
th e
I/ O Mo d ul e ’s m ai n b o ar d . T h e D C p ow e r
requirements of the I/O panel are as follows:
• Nominal input voltage: 7.5V
• Peak current consumption: 930mA
• Average input current: 630mA
The DC power cable should be attached to connector
CN8. Care should be taken to apply the correct DC
polarity. Power connection of the main board is listed
in Table 2-2.
Figure 2-2. CN8 - DC Power Connector
2.3.1 AC Wiring/Installation
The I/O Module is to be permanently mounted with a
readily accessible disconnect device incorporated in
the building installation wiring. All wiring is to be
done in accordance with the National Electric Code
(NEC).
2.4 Fiber Optics Assembly
The I/O Module is equipped with duplex fiber optic
ports for communicating with other devices located in
the safe or hazardous area. It provides electrical
isolation and eliminates the use of I/O barriers
commonly used in intrinsically safe systems. The
fiber optic wires are plastic; no polishing or further
preparation is required. See Figure 2-1 on page 2 for
the location of the fiber optic ports on the
I/O Module
main board.
NOTE: The fiber optic connections between the
indicator and the I/O Module need to be cross-linked.
The optical output of the indicator should be attached
to the input of the
I/O Module , and the indicator’s
input to the module’s output.
Use the following steps for assembling the fiber optics
connectors of the
I/O Module :
1. Cut off the ends of the fiber optic cable with a
single-edge razor blade or sharp knife. Try to
obtain a precise 90º angle.
2. Insert the fiber through the locking nut and
into the connector until the core tip seats
against the internal micro-lens.
3. Screw the connector locking nut down to a
snug fit, locking the fiber in place.
4. Secure duplex fiber optic cable to wire tie
mounting button located on I/O Module
circuit board (see Figure 2-1 on page 2) using
wire ties included in parts kit.
Figure 2-3. Fiber Optic Connector
2.4.1 EDP and Printer Ports
The indicator communicates with external devices
through the
I/O Module located in a remote location.
The I/O board serves as a gateway with several types
of communication interfaces (RS-232, RS-422,
RS-485, and 20mA current loop). The following
sections explain how to install and configure the
c o m m u n i c a t i o n i n t e r f a c e s t o e s t a b l i s h s e r i a l
communications with peripheral devices.
2.4.2 RS-232 Communications
To attach a PC or other device to the I/O Module ’s
RS-232 ports, select RS-232 standard in the indicator
SERIAL menu for the appropriate port (EDP and/or
printer). EDP and printer ports should be configured
separately. See Table 2-3 below for information on
connecting RS-232 communications.
Pin Description
1 +VDC
2 Ground
Table 2-2. Power Connections (CN8)
GND +VDC
Connector
CN8
Pin Description (Sign)
1 Signal Ground (GND)
2 - 4 —
5 Receive Data (RXD)
6 - 7 —
8 Transmit Data (TXD)
Table 2-3. RS-232 Connections (CN2 and CN3)
Optical Fiber
Locking Nut
Positioning Foot
Housing
Lens Mounting Hole
Device
LED