--- updatedAt: 2025-11-05T21:07:55.000Z agentTools: projectIndex: https://esf.eurotech.com/llms.txt --- # Ethernet/IP Driver for AllenBradley This driver allows to interact with AllenBradley PLCs using the EthernetIP protocol. ## Supported PLCs The driver is compatible with the AllenBradley PLCs that implement the "Logix 5000 Controllers Data Access" Ethernet/IP services described in the following document, the document also mentions some of the supported PLCs: * ## Supported features * Read tag and write tag requests. * Decoding/encoding of the following data types: * `BOOL` * `SINT` * `INT` * `DINT` * `REAL` * `BITS` * `STRING` (82 bytes string) * Decoding/encoding arrays of the atomic types above using the JSON format. * Reading any data type as raw byte array data. ## Limitations * Multi dimensional array types are supported only in raw mode. * Decoding/encoding of entire structured data types using the JSON format is not supported (except for the 82 bytes string). It is possible to retrieve atomic fields contained in structured data. * Reading/writing custom string types (string types that are not the default 82 byte string) using the STRING **value.type** is not supported. A possible workaround is reading/writing the `LEN` and `DATA` fields separately and implementing conversions to the String Wires type using a Javascript filter. * Listen mode is not supported by the AllenBradley services. ## Driver configuration The driver provides the following global (instance) configuration options: * **Host**: The hostname or ip address of the PLC. * **Slot**: The slot number (0, 1, ..) of the controller within PLC crate. * **Timeout**: The connection timeout in milliseconds. ## Channel configuration The driver provides the following channel configuration parameters: * **Tag**: The tag to read or write. The tag can refer to array items or structure fields with the following notation: * Array access: `[array index]`, example `myArray[1]` * Struct field access: `.` example `myStruct.myField` The array and field access syntax can be combined. For example the following tags are valid: * `myStructArray[5].myField` * `dataPoint.items[4].nested[3].field` Tag name is case sensitive, channels whose **Tag** parameters differ only in character case will refer to different tags on the PLC. * **Array length**: Enables reading an array or a portion of an array using the JSON format. In this case specifies the number of items to read. If this parameter is specified, **Tag** must refer to an array data point. This parameter must be left empty for channels that refer to atomic types. * **Array offset**: This parameter specifies an offset inside the array addressed by **Tag** to start reading/writing to/from. This parameter is useful if **Array length** is specified as well. This parameter must be left empty for channels that refer to atomic types. Listen mode is not supported by the driver. Using the `Driver.registerChannelListener()` API will fail. Ticking the **listen** flag on AB Asset channels will have no effect. ## Data representation ## Atomic types The following atomic types can be read and written selecting the Wires/Driver numeric and boolean types as **value.type**: * `BOOL`: BOOLEAN and numeric types (zero/non-zero conversion is performed) * `SINT`: numeric types * `DINT`: numeric types * `INT`: numeric types * `REAL`: numeric types * `BITS`: numeric types (value is encoded as a 32 bit integer) Strings must be read/written using the JSON format. ## JSON If `STRING` is used as **value.type**, the driver will return (reads) and require (writes) data encoded in JSON. The format used in the two cases is slightly different. ### Reads The returned value is a JSON object with the following two properties: * **value**: Represents the read value. Can be a of different JSON types: * `boolean`: `BOOL` * `number`: `SINT`, `DINT`, `INT`, `REAL`, `BITS` * `string`: `STRING` * `array`: An array of the supported atomic types, represented as JSON `boolean`s, `number`s or `string`s as described above * **type**: Reports the PLC data type, the allowed values are the following: * `BOOL` * `SINT` * `DINT` * `INT` * `REAL` * `BITS` * `STRUCT` (for the string case) If the value is an array, a `[]` suffix will be added. Examples: ```json { "value": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], "type": "SINT[]" } ``` ```json { "value": 0, "type": "BITS" } ``` ```json { "value": "foo", "type": "STRUCT" } ``` ### Writes For writes using the JSON format, the user must provide a JSON object with a single field: * **value**: Encoded using the same rules as the **value** field for reads Examples: ```json { "value": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] } ``` ```json { "value": 0 } ``` ```json { "value": "foo" } ``` ## Raw requests If `BYTE_ARRAY` is used as **value.type**, the driver will perform a raw request returning the data as encoded by the wire protocol. This request kind supports any data type.\ The returned data will contain a type identification tag followed by the actual data.\ Structure encoding contains the binary representation of the fields encoded in sequence, possibly interleaved by padding bytes.\ See for more information about value decoding.\ This mode only supports transferring data types that fit in a single frame payload, the payload size is reported to be "approximately 500 bytes" by AB documentation. This mode is only supported for reads.