MVI56-DEM
♦
ControlLogix Platform
Reference
Honeywell DE Communication Module
Page 46 of 80
ProSoft Technology, Inc.
March 6, 2008
Command Control Blocks
Block identification codes greater than 9900 are utilized to perform special
functions in the module. Each control block recognized and used by the module
is defined in the following topics.
Cold Boot Block (9999)
Block 9999 performs a cold-boot operation on the module. The format of the
block constructed by the processor is as follows:
Offset Description
Length
0
9999
1
1 to 247
Spare
247
5.2.2 Data
Flow
The movement of data between the transmitter and the processor is important to
understand. The following illustration shows the data movement paths that are
supported in this application. The diagram shows SCAN 3000 implementation,
but functionality will be similar for other interfaces. The SCAN 3000 software will
be supported after the interface to the ControlLogix processor has been defined.
SCAN 3000
A-B PLC
DE Module
Transmitter
Read/Write Database
Write Database
Read Database
Display
Data
Write
Data
Download
(Function = 1)
Upload
(Function = 2)
User Initiated
Down/Upload
Read Only Data
Read/Write Data
Read
Transmitter &
Calculate
Mismatch
Read Data with Calculated Mismatch
Smart
Transmitter
Important: One of the underlying concepts that must be understood is that the processor is
considered the 'owner' of the data. Therefore the contents of the processor data space, in
particular the Write Data space, are the data to which all other data is compared.
Step Description
Power Up
The read database will be populated by the DEM from the Smart Transmitter, and
the write database will remain unchanged from its initial value in the processor.
The user can then choose to upload or download
Read DE
Transmitter
& Calculate
Mismatch
The module continuously transfers from the Smart Transmitter database to the
read database, comparing the Write and Read files in the processor for mismatch.
The module performs a mismatch comparison between the two and sets the
status in the read database accordingly
