Reference MVI56-DEM
♦
ControlLogix Platform
Honeywell DE Communication Module
ProSoft Technology, Inc.
Page 39 of 80
March 6, 2008
5.1.4 Functional
Specifications
Backplane data transfer via input/output files
Interfaces with Honeywell smart transmitters operating in the DE mode
Support multiple DE channels CLX - up to 16 Channels with single PV
transmitter, multivariable transmitters
Instrument database mismatch verification
Interfaces directly to Honeywell Field Terminal Assembly (FTA)
Single cable connection from DEM module to FTA
External 24 VDC source connection on front of DEM module for instrument
loop power
LEDs for visual module status
o
Module active
o
Module fault
Operation via simple ladder logic
5.2 Functional
Overview
This section provides an overview of how the MVI56-DEM module transfers data
using the DEM protocol. You should understand the important concepts in this
chapter before you begin installing and configuring the module.
5.2.1 General
Concepts
The following discussion explains several concepts that are important for
understanding the operation of the MVI56-DEM module.
DE Channels
The MVI56-DEM module has been designed to provide a tightly integrated
Communication Interface between the Rockwell Automation ControlLogix
platform and the family of Honeywell Smart Transmitters.
The module consists of two DE CPU micro-controllers, each of which provide
communications with 8 DE Smart Transmitters. The subsequent figure shows the
following functional components on the module:
A Primary DEM controller responsible for the overall operation of the board,
including:
o
Access to Shared Ram between DE CPU #1, #2
o
Backplane communications with Rockwell Automation processor
o
Transferring data from DE processors to processor
o
Transferring write commands from the processor to DE processors
o
Data Base Mismatch comparisons
o
LED Status indicators
Two DE CPU 68HC11 micro-controllers, each with the following:
o
Eight data receivers which provide input signal conditioning (noise
filtering, surge limiting, etc.) for the serial data inputs
o
An output channel selector and driver circuitry allowing the DE processor
to output data base write commands to any channel
