Prosoft-technology MVI69E-MBS Bedienungsanleitung PDF herunterladen (Seite 142)

Reference MVI69E-MBS ♦ CompactLogix Platform

User Manual Communication Module

Page 142 of 162 ProSoft Technology, Inc.

January 6, 2014

The MBS Add-On Instruction handles the receipt of all Modbus write functions

and to respond as expected to commands issued by the remote Modbus Master

device.

Note: Mutual exclusion on Pass-Through Block IDs 9956, 9957, 9958, and 9959 from both ports -

If both ports are configured as slave ports, when both of the slave ports receive write commands

with the same Function Code, which would need to use the same block identifier from the above

list, the module processes the command from the port which first received the command.

The module returns an Exception Code error code 6 (Node is busy - retry command later error)

from the other port that received the command last. The Master retries the command on the busy

port after a short delay. This prevents Pass-Through blocks on both ports from overwriting each

other.

Block 9956: Request from Module to Processor

Offset

Description

Read Block ID: 9956

Write Block ID: 9956

Number of word registers in Modbus data set

Starting address for Modbus data set

4 to (n+1)

Data (Length in words = n - 2)

Where n = 60, 120, or 240 depending on the Block Transfer Size parameter.

The ladder logic is responsible for parsing and copying the received message

and performing the proper control operation as expected by the Master device.

The processor must then respond to the pass-through control block with an

output image write block with the following format.

This informs the module that the command has been processed and can be

cleared from the pass-through queue.

Block 9956: Response from Processor to Module

Offset

Description

Write Block ID: 9956

1 to n

Spare (Length in words = n - 2)

1 2 ... 137 138 139 140 141 142 143 144 145 146 147 ... 161 162

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Prosoft-technology MVI69E-MBS Bedienungsanleitung Seite 142