Innotech Genesis V4 System - Manual (Page 93)

Installation Instructions for Innotech Genesis Systems
Edition 011100
A-12
WARNING
IF THE EARTH TERMINAL IS NOT CONNECTED TO THE
ELECTRICAL EARTH, THE CABLE CONNECTED TO PORT 2
CAN REACH DANGEROUSLY HIGH VOLTAGES.
Port 2 should be connected to the remote devices - the devices supplied from a different
switchboard.
If the Comms cable connection to Port 1 is an end connection and the Repeater Module is
not the earth point for the screen, the screen of the Comms cable must not be connected to
the terminal. If the Comms cable is looped through Port 1 and the repeater is not the earth
point for the screen, the screens of the two Comms cables will have to be joined but not
connected into the terminal.
Because Port 2 is isolated, the screen(s) of the Comms cable(s) can always be joined in the
terminal.
A-4.2.7. GENII MPI Modem and Printer Interface. The GENII MPI Modem
and Printer Interface can be used with both the Genesis I and Genesis II Digital Controllers.
The MPI is supplied with a double insulated plug pack, which isolates the MPI power
supply from the electrical earth. But, when a printer or PC is connected to the MPI, it will
be connected to the electrical earth via the printer and/or PC cables. See Figure A-12
The Comms is connected to the MPI via the RJ11 socket on the rear of the MPI. The top
portion of Figure A-12 shows the socket connections and the cable as supplied. The
standard order for conductor colours is shown, but they may change and, therefore, should
always be checked before connecting.
To isolate the screen of the Comms cabling from electrical earth at a non-isolated MPI, do
not connect the two GND conductors of the flat MPI cable to the screen(s) of the Comms
cables at the wall connection. This is not an isolated connection for the data conductors.
To provide isolation for the data conductors, an MPI fitted with RS485 isolation ICs must
be used. The two GND conductors should be connected to the screen(s) of the Comms
cable when an isolated MPI is used. Connecting the screen(s) of the Comms cable(s)
completes the internal over-voltage protection on the MPI data connections.