Shared Memory Configuration Page - Comtrol DeviceMaster EtherNet/IP-Modbus EIP-MOD User Manual

Shared Memory Configuration Page

7.4. Shared Memory Configuration Page

The Shared Memory functionality enables multiple methods for communicating between a wide variety of
EtherNet/IP controllers, Modbus masters and Modbus slave devices.
The Shared Memory interface contains eight 200 Holding Register blocks and eight 320 Coil blocks.
• EtherNet/IP controllers can access the Shared Memory through Class1 connections, the Modbus Object,
and Write-to-Tag/File and Read-from-Tag/File interfaces.
• All Modbus masters, (Modbus/TCP, serial Modbus RTU/ASCII, and Modbus RTU/ASCII over Ethernet
TCP/IP), can read the contents of the Shared Memory blocks.
• Data Mapping configurations can read Shared Memory blocks.
• Write access can be controlled to each Holding Register and Coil block. Each block can be configured to:
- Provide all masters, expect Class1, write access
- Can be restricted to:
- A port-specific serial master
- A Modbus/TCP master
- An Ethernet TCP/IP master
- EtherNet/IP Class1
- Modbus Object message(s)
- Tag/File to Modbus Data Mapping configuration(s).
- Modbus to Modbus Data Mapping configuration(s)
• The Shared Memory contents can be displayed and cleared via the embedded web pages.
• Diagnostics for each block include read, write and blocked write message counts.
• Blocked write messages are recorded in the Write Violation Log.
• Special EtherNet/IP Class1 handling:
- In order to read from a Shared Memory block via a Class1 connection, the shared memory block must
be Class1 Read Enabled. The Class1 connection receive data contents and size are determined by
which Shared Memory blocks are read enabled.
- In order to write to a Shared Memory block via a Class1 connection, the shared memory block Write
Master(s) setting must be set to EIP Class1. Only then may an EtherNet/IP Class1 connection write
to the Shared Memory. That is because the Class1 connection writes continually to the block and over
write any data written by another controller.
This table displays the supported Holding Register Block Function Codes:
78 - Chapter 7. Data Mapping Menus
Function Code
3 Read Holding Registers
4 Read Input Registers
6 Write Single Register
16 Write Multiple Registers
22 Write Mask Register
23 Read Write Registers
Description
DeviceMaster EIP-MOD User Guide: 2000664 Rev. A