ProSoft Technology MVI71-DFNT User Manual

Page 32

Installing and Configuring the Module

MVI71-DFNT ♦ PLC 5

User Manual

EtherNet/IP Client/Server Communication Module

Page 32 of 175

ProSoft Technology, Inc.

February 3, 2011

In order to interface the virtual database with DF1 slave devices, you must

construct a command list. The commands in the list specify the DF1 slave device

to be utilized, the function to be performed (read or write), the data area in the

device to interface with and the position in the virtual database to be associated

with the device data. There is a separate command list for each DF1 master

device emulated. The list is processed from top (command #0) to bottom. A poll

interval parameter is associated with each command to specify a minimum delay

time between the issuance of a command. If the user specifies a value of 10 for

the parameter, the command will be executed no more frequently than every 10

seconds for the serial implementation and 1 second for the network

implementation.

Command List

Write commands have a special feature, as they can be set to execute only if the

data in the write command changes. If the data in the command has not changed

since the command was last issued, the command will not be executed. If the

data in the command has changed since the command was last issued, the

command will be executed. Use of this feature can lighten the load on the DF1

network. In order to implement this feature; set the enable code for the command

to a value of 2.
If the module is configured for the serial DF1 half-duplex protocol, the module

can act as a master device routing messages between attached slave devices.

This peer-to-peer communication is defined in the DF1 protocol specification.

The master polls each DF1 slave device until no more data is available from the

device. Response messages from the slaves that have a destination address that

do not match the module are routed with a request message header back out

onto the network. This facility offers communication between the slave devices

for control and data monitoring. This feature is not available if the module is

configured for DF1 full-duplex mode (point-to-point).
The module supports numerous commands. This permits the module to interface

with a wide variety of DF1 protocol devices. This includes PLC2, PLC5, SLC-500

series, MicroLogix and ControlLogix processors. Additionally, other devices

supplied by Rockwell Automation that use the DF1 protocol are supported.
The format of each command in the list depends on the function being executed.

To simplify command construction, the module uses its own set of function codes

to associate a command with a DF1 command/function type. The tables below

list the functions supported by the module:

Basic Command Set Functions

Function

Code

Comman

Function Definition

PLC5

SLC500 &

MicroLogix

Power-

monitor II

ControlLogix

0x00

N/A

Protected Write

0x01

N/A

Unprotected Read

0x02

N/A

Protected Bit Write

0x05

N/A

Unprotected Bit Write X

0x08

N/A

Unprotected Write