ProSoft Technology MVI46-MBP - Manual (Page 39)

Reference MVI46-MBP ♦ SLC Platform
Modbus Plus Communication Module
ProSoft Technology, Inc. Page 39 of 101
February 19, 2008
ƒ Function codes accepted (as a Slave): 1, 2, 3, 4, 5, 6, 15, 16
ƒ Function codes transmitted (as a Master): 3, 16
Global Data Specifications
The MBP module actively exchanges global in (32 words max. per node) and
global out (32 words max.) data on the Modbus Plus network. Priority is given to
these data types to provide a high speed mechanism for the transfer of control
data.
Modbus Slave Mode Specifications
ƒ
Supports broadcast commands from host
ƒ Communication error codes returned to ladder logic
Modbus Master Mode Specifications
ƒ
Command list support of up to 100 commands
ƒ Conditional and continuous command list polling
ƒ Each command list entry is fully configurable for function register to/from
addressing and word/bit count/word and byte swap
ƒ Event driven bit and register write commands (ladder logic controlled)
ƒ Supports sending of broadcast commands
ƒ Communication status error codes returned to ladder logic on a per command
basis
5.2 Functional Overview
This section provides an overview of how the MVI46-MBP module transfers data
using the MBP 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 MVI46-MBP module.
Module Power Up
On power up the module begins performing the following logical functions:
1 Initialize hardware components
o
Initialize SLC backplane driver
o
Test and Clear all RAM
o
Reset Modbus Plus Chipset
2 Wait for Module Configuration from SLC processor
3 Initialize Module Register space
4
Initialize Modbus Plus Chipset
5 Enable Global Input task
6 Enable Global Output task
7 Enable Slave Driver
8 Enable Master Driver