Introduction

Use Control Expert to create a collection of device derived data types (DDDTs) and variables that support communications and the transfer of data between the PAC and the various local slaves, distributed devices, and corresponding I/O modules.

You can create DDDTs and corresponding variables in the Control Expert DTM. Those program objects support your network design.

NOTE: The default device name depends on the firmware version installed in the selected CPU, and may be one of the following:

  • T_BMEP58_ECPU

  • T_BMEP58_ECPU_EXT

  • T_M_ECPU_HSBY

Use the DDDTs for these tasks:

  • Read status information from the Ethernet communication module.

  • Write control instructions to the Ethernet communication module.

You can double-click the name of the DDDT in the Project Browser at any time to view its properties and open the corresponding EDS file.

NOTE: For applications that require multiple DDDTs, create an Alias name that logically identifies the DDDT with the configuration (module, slot, local slave number, etc.).

DDDT Variables

You can access the DDDTs and the corresponding variables in Control Expert and add them to a user-defined Animation Table. Use that table to monitor read-only variables and edit read-write variables.

Use these data types and variables to perform these tasks:

  • Read the status of connections and communications between the Ethernet communication module and distributed EtherNet/IP and Modbus TCP devices:

    • The status is displayed in the form of a HEALTH_BITS array consisting of 32 bytes.

    • A bit value of 0 indicates the connection is lost or the communication module can no longer communicate with the distributed device.

  • Toggle a connection ON (1) or OFF (0) by writing to a selected bit in a 16-word DIO_CTRL array

  • Monitor the value of local slave and distributed device input and output items that you created in Control Expert.

NOTE: The HEALTH_BITS array is not copied to the standby CPU in a Hot Standby switchover. The DIO_CTRL array is copied to the standby CPU in a Hot Standby switchover.

Displaying the Order of Input and Output Items

View the DDDTs in Control Expert (Project Browser > Variables & FB instances > Device DDT Variables). The Data Editor is now open. Click the DDT Types tab.

The Data Editor displays each input and output variable. When you open the first input and output variables, you can see both the connection health bits and the connection control bits.

This table shows the rule assignment for connection numbers:

Input Variables

Order

Output Variables

Modbus TCP input variables (note 1)

1

Modbus TCP output variables (note 1)

ERIO drop input variables

2

  

local slave input variables (note 2)

3

local slave output variables (note 3)

EtherNet/IP input variables(note 1)

4

EtherNet/IP output variables (note 1)

NOTE 1: DDDTs are in this format:

  • i. by device number

  • ii. within a device (by connection number)

  • iii. within a connection (by item offset)

NOTE 2: Local slave variables are in this format:

  • i. by local slave number

  • ii. within each local slave (by item offset)