AB CompactLogix Ethernet FreeTag

8 min

Review the following information for setting up and configuring the AB CompactLogix Ethernet FreeTag driver.

Note: We recommend this driver for CompactLogix and ControlLogix PLCs, as it provides the best stability over other compatible drivers. If you prefer speed over stability, you can use the AB CompactLogix Ethernet Advanced.

Litmus Edge Compatible Series

Compatibility parameter	Compatible items
Driver type	Ethernet
Validated devices/series	CompactLogix ControlLogix
Replaces Gen 1 driver(s)	AB CompactLogix (Gen1) AB ControlLogix (Gen1) Learn more about Gen1 and Gen2 Driver Differences

To set up and configure this device in Litmus Edge, you will need to do the following:

Step 1: Set up and Configure the PLC Device
Step 2: Set up the PLC Device in Litmus Edge DeviceHub
Step 3: Configure the List of Registers

Step 1: Set up and Configure the PLC Device

If the device is configured for Ethernet access, find its network parameters. Otherwise, follow the steps below.

To configure your device:

Start the Studio 5000 Logix Designer application.
Select File > Open, then select your PLC project.
In Controller Organizer, right-click the device and select Properties from the popup menu. The Module Properties dialog box appears.
Select the Port Configuration tab.
Copy aside the IP address from the IP address field.

Step 2: Set up the PLC Device in Litmus Edge DeviceHub

Configure the following parameters when you Connect a DeviceConnect a Device with this driver. Update default values to the specific setup of your device.

Parameter	Value
Type	Allen-Bradley
Driver	AB CompactLogix Ethernet FreeTag
Network Address	The device address you defined in Step 1
Port	44818
Slot	0

Step 3: Configure the List of Registers

Browse for tags to add to this FreeTag device. See Browse Tags to learn more. Alternatively, when you Add Tags, type the tag name in the Name field exactly as it is defined in the device (case-sensitive). You can find a list of tags by navigating to Controller Organizer > Controller > Controller Tags in Studio 5000 Logix Designer.

The following data types are supported:

bool
byte
sint
int
dint
real
dword
lint
lreal
string

Addressing Tips

To access the bits of a dint tag, use the data type bool and append the bit address (.0 to .31) to the name of the dint tag.
To access the elements of a two- or three-dimensional array, use multiple square brackets instead of commas to separate the indices. For example, if the array in RSLogix 5000 has the name MyArray with the data type dint[2,2,2], you can access the 0th index by entering MyArray[0][0][0] in Litmus Edge.

Refer to the following tag parameters in Litmus Edge.

Tag Parameters

Name: Enter the case-sensitive register name exactly as it is defined in the PLC.

Value Type: Select a data type from the drop-down list.

Polling Interval: Enter a value in seconds. This determines how often the tag should poll the register for data.

Tag Name: Enter a name for the tag.

Description (Optional): Enter a description for the tag.

Tag Formula: Enter a formula for the tag to process the generated data. Two variables are permitted: value (current tag value) and timestamp (current tag UNIX time in milliseconds). The following math functions are available:

sqrt

power: power(x) performs the operation 10^x.

log: log(x) is the natural logarithm (the logarithm is in base e).

exp: exp(x) performs the operation e^x.

Only Publish on Change of Value: Select the checkbox to only publish NATS messages when the value parameter changes to a new value. Change of Value only applies to boolean, numeric (such as int or float), and simple string data types. It does not apply to complex types, such as JSON or array. Poll-once topics will not be affected by Change of Value settings. These topics will still only see a single message.

Meta Data: Metadata summarizes basic information about data. This feature allows you to define key-value pair data for the device output payload later on. Metadata can then be used to find, use, and reuse particular instances of data.

Note: If you use special characters in meta data key names, the special characters are replaced with underscore characters in the payload. This can cause two key names to be combined into one. For example, configuring the key names a**b and a&&b will cause only one key name to be created (a__b).