DESCRIPTION AND OPERATION
MPI MODULE CIRCUITRY
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I-E96-203C
Elsag Bailey
Process A utom ation
The MPI module connects to an NTMP01 Multi-Function Pro-
cessor Termination Unit. I/O signals enter or leave the MPI
module through an NKTU01 or NKTU11 termination unit
cable connected to an NTMP01 termination unit. Another
route for the signals is through an NKTU02 or NKTU12 termi-
nation unit cable connected to an NIMP01 or NIMP02 termi-
nation module. If the serial channels are used in a redundant
configuration, each MFP module must be connected to an
MPI module. Redundant MPI/termination module combina-
tions require two termination modules: the NIMP01 and
NIMP02 Multi-Function Processor Termination Modules.
MPI MODULE CIRCUITRY
The MPI module contains a dual universal asynchronous
receiver/transmitter (DUART) circuit, SCSI processor, clock/
timer circuit, buffers and optical isolators, and power cir-
cuitry. Figure
shows a block diagram of the MPI circuitry.
Serial Channels (DUART)
There are two independent, general purpose serial channels
on the MPI module. A DUART circuit on the MPI module sup-
plies the serial channels with handshaking signals. There are
no clock signals passed from the MFP module to the MPI
module. Clock signals for the baud rate generator are derived
from an on-board 7.3728-megahertz oscillator.
One use for serial ports is language support (C and Basic).
Each channel can support standard baud rates up to
19.2 kilobaud. Standard D-type connectors are available on
the termination unit or termination module. Jumpers, drivers
and receivers on the termination unit or module convert the
two serial channels (RS-485) from the MPI module into two
RS-232-C ports or one RS-232-C port and one RS-485 port.
These channels are optically isolated by the NTMP01, NIMP01
or NIMP02 termination device. This optical isolation elimi-
nates the potential of damage from ground currents.
Figure 2-2. MPI Functional Block Diagram
IMMFP03
CONTROL
RXD/TXD
BUFFERS
DUART
DATA
CLOCK/
TIMER
ISOLATION
RS-485, RS-232-C
SAC/DCS
STATION LINK
DIGITAL
I/O
TP25208C
TU OR TM