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Logix Tag Support

The EtherNet/IP Device Service supports tags produced and consumed by Logix controllers.

Logix Tag Device Profile

Logix Tag Resources

To create a device resource for a Logix Tag, the following attributes are required:

Attribute Description Valid Values
type Informs the device service of the resource type, in this case, logixTag logixTag
tagName The name of the programmed tag within the PLC <tag name>
arraySize The number of array elements, if the Tag is an array
Note: This resource is only used if an entire Array Tag is to be read at once. 		Any value between: 0 and 200

Logix Tag Resource Examples

Provided below is an example of Tags that may be programmed into a PLC through Studio 5000:

Tag Name Data Type
test_dint DINT
test_real REAL
bool_array[0] BOOL
bool_array Array

Resources for all the above tags can be seen below

{
   "name":"test_dint",
   "description":"Double Integer Value",
   "attributes":{
      "type":"logixTag",
      "tagName":"test_dint"
   },
   "properties":{
      "value":{
         "type":"int16",
         "readWrite":"RW"
      }
   }
},
{
   "name":"test_real",
   "description":"Floating point value",
   "attributes":{
      "type":"logixTag",
      "tagName":"test_real"
   },
   "properties":{
      "value":{
         "type":"float32",
         "readWrite":"RW"
      }
   }
},
{
   "name":"bool_array[0]",
   "description":"First element of bool array",
   "attributes":{
      "type":"logixTag",
      "tagName":"bool_array[0]"
   },
   "properties":{
      "value":{
         "type":"bool",
         "readWrite":"RW"
      }
   }
}
{
   "name":"bool_array",
   "description":"First element of bool array",
   "attributes":{
      "arraySize":10,
      "type":"logixTag",
      "tagName":"bool_array"
   },
   "properties":{
      "value":{
         "type":"Uint8Array",
         "readWrite":"R"
      }
   }
}

The example above shows that the device service has the ability to read and write to individual elements from array tags, in this case: bool_array[0] is the first element of bool_array and has the ability to read and write to it.

You can also read (but not write) to the whole array tag itself. In this case: bool_array is output using the Uint8Array data type. This will output the array as a list.