DESCRIPTION AND OPERATION
I-E96-225A
2 - 3
CTT PORT
The IMCPM03 module communicates with the CTT terminal
via the round five-pin connector on the faceplate. Messages
received from the CTT terminal are transmitted on Controlway
or module bus, but using the source module address of the
IMCPM03 module in place of the module address of the CTT
terminal. Only replies to messages initiated by the CTT termi-
nal are transmitted to the CTT terminal. A CTT terminal con-
nected to the Controlway through an IMCPM03 module is a
message-initiating device only. The IMCPM03 module cannot
relay messages to the CTT terminal that are initiated from
other modules within the process control unit.
DB-9 EWS PORT
An optically isolated DB-9 connector is located inside the face-
plate on the circuit board (P6) for use as an EWS port.
MICROPROCESSOR
A 16-megahertz microprocessor is responsible for module oper-
ation and control. The operating system instructions reside in
the read-only memory (ROM). The processor constantly retrig-
gers the machine fault timer (MFT) circuit. If the processor or
software fails and the MFT circuit is not reset, the MFT issues a
board-wide reset and the status LED turns red. In this state,
the IMCPM03 module will not function until it is reset.
CLOCK AND TIMER
The clock section provides the clock signals to drive the module
at 16 megahertz. Additionally, it supplies the clock signals for
the on-board serial port. The timer section is the system clock
that keeps the processor task scheduling at the proper
intervals.
MEMORY
There are 256 kilobytes of ROM and 512 kilobytes of RAM. The
ROM holds the operating system instructions for the proces-
sor. The RAM provides temporary storage.
A key feature of the module memory is that it requires no wait
states. The processor does not need to wait any clock cycles
(zero wait states) before it can check the data in memory. This
results in quicker operation.
