Innotech Genesis V4 System - Manual (Page 94)

Installation Instructions for Innotech Genesis Systems
Edition 011100
A-13
Figure A-12. GENII MPI Modem and Printer Interface.
A-4.2.8. Genesis I Non-Isolated Comms. Because Genesis I Digital Controllers
do not have links between the RS485 ICs and the Comms terminals, the Comms terminals
are permanently connected to the Digital Controller Common and to Terminal 2.
Therefore, the screen(s) of the Comms cable(s) must be connected to Terminal 91 of only
one Digital Controller, as shown in the Figure A-13.
At looping connections the screens must be joined externally as shown in Figure A-13. The
screen must not be connected to the terminal at an end connection that is not the earthing
point for the screens.
For Digital Controllers supplied from one switchboard or mounted in one control panel, the
screen is earthed at one Digital Controller only.
MODEM
PC
PRINTER
A non-isolated MPI has the three DB connector shells and the pins shown connected
to COMMON. When a Printer or PC is connected, the RS485 Comms is earthed.
An isolated MPI has the three DB connector shells and the pins shown connected
to COMMON. When a Printer or PC is connected, the RS485 Comms are NOT earthed.
MODEM
PC
PRINTER
COMMS CABLE CONNECTION ON MPI
G+ G-
Gn
d
Gn
d
N+ N-
Socket on MPI viewed
from rear of MPI
Wh
it
e
Bl
ack
Re
d
Gre
e
n
Y
e
llow
Bl
ue
Plug and Cable viewed as
plugged into rear of MPI
N- (blue)
N+ (yellow)
Gnd (green)
Gnd (red)
G- (black)
G+ (white)
NOTE
On some units, wire colours
may be different than as
shown here.