Connecting to Logix

note

This driver is optimized for Logix family devices with firmware version 21+, but supports earlier firmware versions with significantly reduced performance.

Connecting to ControlLogix v21

Watch the video

Connect to an Allen-Bradley Logix Device

caution

This module requires the OPC UA module to be installed and enabled. If the OPC UA module is not installed or is disabled, this module will fault with a warning in the logs and display the state as "Faulted Missing Dependency" on the Config > Modules page.

1. Go to the Config section of the Gateway Webpage.

2. Scroll down and select OPC UA > Device Connections.

   

3. On the Devices page, find the blue arrow and click on Create new Device.

4. Select Allen-Bradley Logix Driver, and click Next.

   

5. Fill in the following fields:

   • Name: CLX
   • Hostname: type the IP address for the PLC, for example 10.20.1.54.

   Leave the default values in the remaining fields.

   

6. Click Create New Device.

7. The Devices page is displayed showing the ControlLogix device is added to Ignition. The Status will show as Disconnected and then Connected.

   

8. To see all the Tags, go to OPC Client > Quick Client in the Config section. On the OPC Quick Client page, expand the CompactLogix folder and in the Global folder you can see all the tags.

Driver Implementation

One noteworthy implementation of the Logix driver is how boolean arrays are handled. Boolean arrays items are browsed as members of a 32-bit DWORD. Thus, a BOOL[64] in the PLC is implemented as DWORD[2] in the driver.

Below is a table representing how members of a boolean array items are mapped in the PLC, compared to the Logix driver's implementation.

PLC Mapping	Driver Implementation
boolTag[0]	boolTag[0].0
boolTag[31]	boolTag[0].31
boolTag[32]	boolTag[1].0
boolTag[63]	boolTag[1].31

The Logix driver also supports the following datatypes:

• DT (Date/Time)
• LDT (Date/Time [ns])
• LTIME (LTime [ns])
• TIME (Decimal)
• TIME32 (Time32 [us])

Device Connection Settings

The General settings are common to all Allen Bradley devices, and the Connectivity settings are device dependent.

General

Name	Description
Name	The user-defined name for this Device. The name chosen will show up in OPC Item Paths and under OPC-UA Server > Devices of the Configure page of the Gateway. The Device Name must be alphanumeric.
Description	The user-defined description for the device. This is only used as a note to differentiate between devices.
Enable Device	Only devices that are enabled appear in Connections > Devices of the Status page of the Gateway and thus have their tags available for use.

Connectivity

Name	Description
Hostname	This is the IP Address of the ControlLogix Ethernet module (1756-ENET) to route through to connect a ControlLogix processor. EthernetIP protocol on TCP port 44818 (0xAF12) is used to communicate to ControlLogix processors.
Port	Port to connect to the remote device.
Local Address	The local address to connect from when establishing a TCP connection. If left blank, then the driver will simply pick an available address.
Timeout	After sending a request to the ControlLogix processor, the Communication Timeout setting is the amount of time in msec to wait for a response before treating it as a failure.
Max Concurrent Requests	The number of requests that Ignition will try to send to the device at the same time. Increasing this number can sometimes help with your request throughput, however increasing this too much can overwhelm the device and hurt your communications with the device.
Slot Number	The Slot Number value is the zero based ControlLogix chassis slot number of the ControlLogix processor to connect to.
Connection Path	If specified, the slot number setting is ignored for this connection path to the processor. Be sure to terminate the path with backplane and slot number.

Advanced

Name	Description
Automatic Rebrowse	Monitor for tag additions and UDT changes and automatically initiate a re-browse when detected. If this is disabled tags will only be browsed when connecting and reconnecting. (Default is true.)
Identity Request Frequency	Frequency, in milliseconds, that the request to read CIP Identity Object attributes occurs at. (Default is 5,000.)
CIP Connection Size	The CIP connection size to use during Forward Open requests. (Default is 500.)
CIP Connection Timeout	Target timeout, in milliseconds, for CIP connections and RPI. (Default is 16,000)