ProSoft Technology inRAx MVI56-CAS, Руководство пользователя

Страница: 56 / 86

MVI56-CAS ♦ ControlLogix Platform Reference
Teledyne CA Slave Module
Page 56 of 86 ProSoft Technology, Inc.
December 26, 2007
This will inform the module that the command has been processed and can be
cleared from the pass-through queue.
5.2.6 Data Flow Between MVI56-CAS Module and ControlLogix
Processor
The following topics describe the flow of data between the two pieces of
hardware (ControlLogix processor and MVI56-CAS module) and other nodes on
the TCA network under the module's different operating modes. Each port on the
module is configured to emulate a TCA slave device. The operation of each port
is dependent on this configuration. The sections below discuss the operation of
each mode.
Slave Driver
The Slave Driver Mode allows the MVI56-CAS module to respond to data read
and write commands issued by a master on the TCA network. The following flow
chart and associated table describe the flow of data into and out of the module.
0
4999
Database
Addresses
ControlLogix
Controller Tags
Slave
Mode
Driver
Status
Configuration
Configuration
Data
Status
from Module
Register
Data
storage
Register
Data
Processor Memory CAS Module Backplane Interface
Configuration
Status
Read Functions
Write Functions
Step Description
1
The TCA slave port driver receives the configuration information from the ControlLogix
processor. This information configures the serial port and define the slave node
characteristics. Additionally, the configuration information contains data that can be
used to offset data in the database to addresses requested in messages received from
master units.
2 A Host device issues a read or write command to the module's node address. The port
driver qualifies the message before accepting it into the module.
3 After the module accepts the command, the data is immediately transferred to the
processor or from the internal database in the module. If the command is a read
command, the data is read out of the database and a response message is built. If the
command is a write command, the data is written directly to the processor and a
response message is built.
4 After the data processing has been completed in Step 2, the response is issued to the
originating master node.
5 Counters are available in the Status Block that permit the ladder logic program to
determine the level of activity of the Slave Driver.