Working with Device DDTs

Introduction

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

You can create DDDTs and corresponding variables in the Control Expert to support your network design.

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 file.

View the Device DDTs

View the DDDT characteristics of the BMENOC0321 module in Control Expert:

Step	Action
1	In a Control Expert project, add a BMENOC0321 module.
2	Build the Control Expert project.
3	In the Variables & Feedback Instances tab, view the variables.

These are the default characteristics of the BMENOC0321 module in the Variables tab:

default variable name: BMENOC0321 (Unity Pro v11.0)
default variable type: T_BMENOC0321 (Unity Pro v11.0)

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

Displaying the Order of Input and Output Items

In the Project Browser, view the DDDTs.

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 (DIO_HEALTH) and the connection control (DIO_CTRL) bits.

This table shows the rule assignment for connection numbers:

Inputs	Order	Outputs
health bits (note 1)	1	control bits (note 1)
Modbus TCP input variables (note 2)	2	Modbus TCP output variables (note 2)
local slave input variables (note 3)	3	local slave output variables (note 3)
EtherNet/IP input variables (note 2)	4	EtherNet/IP output variables (note 2)
NOTE 1: Health and control bits are in this format: i. By device type: a. Modbus TCP b. local slave c. EtherNet/IP ii. Within each device type: a. by device or local slave number b. within a device (by connection number) NOTE 2: Device variables are in this format: i. by device number ii. within a device (by connection number) iii. within a connection (by item offset) NOTE 3: Local slave variables are in this format: i. by local slave number ii. within each local slave (by item offset)