# Allen-Bradley DF1

DF1 is a proprietary communication protocol developed by Rockwell Automation, primarily used for data exchange between its Allen Bradley series PLCs (Programmable Logic Controllers) and other devices.
The EMQX Neuron Allen Bradley DF1 driver supports point-to-point communication and data transmission through serial communication lines.

For the generic steps, see [Create a Southbound Driver](../south-devices.md) and [Groups and Tags](../../groups-tags/groups-tags.md).

## Add Driver

On **Data Collection → South Devices**, click **Add Device**.

- Name: The name of this device node.
- Driver: Select the **Allen-Bradley DF1** driver.

## Connection Parameters

Click the driver card to open the **Device Configuration** page and fill in:

| Parameter                 | Description                                                    |
| -------------------- | ------------------------------------------------------- |
| **Recv Timeout** | The time of the system waits for a device to respond to a command.  |
| **Send Interval** | 	The waiting time between sending each read/write command. Some serial devices may discard certain commands if they receive consecutive commands in a short period of time. |
| **Serial Port** | The path to the serial device when using a serial connection, e.g., /dev/ttyS0 in Linux systems. |
| **Stop Bits** | Serial connection parameter. |
| **Parity** | Serial connection parameter. |
| **Baud Rate** | Serial connection parameter. |
| **Data Size** | Serial connection parameter. |

## Tag Configuration

The data types and address formats supported by this driver are listed below.

### Data Types

* INT16
* UINT16
* INT32
* UINT32
* FLOAT
* BIT
* STRING

### Address format

> FILE NUM:ELEM[.BIT][#ENDIAN]\[.LEN\[H]\[L]]

For example, N7:0

#### **FILE**

Required, File is the type or the file.
| FILE | FILE TYPE |
| ---- | --------- |
| U    |  STATUS     |
| B    |  BIT        |
| T    |  TIMER      |
| C    |  COUNTER    |
| R    |  COUNTROL   |
| N    |  INTEGER    |
| F    |  FLOAT      |
| S    |  STRING     |
| A    |  ASCII      |

#### NUM

Required, NUM is the number or the file.

#### ELEM

Required, ELEM is the number or the elem.

#### **.BIT**

Optional, specify a specific bit in a register, as:
| Address         | Data Type | Description                                                |
| ----------- | ------- | --------------------------------------------------- |
| N7:0.0  | bit     | Refers to INT FILE 7 , address 0, bit 0.     |
| N7:0.15 | bit     | Refers to INT FILE 7 , address 0, bit 15.    |

#### **#ENDIAN**

Optional, byte order, applicable to data types int16/uint16/int32/uint32/float/, see the table below for details.
| Symbol | Byte Order | Supported Data Types        | Note |
| --- | ------- | ------------------ | ----- |
| #B  | 2,1 or 8,7,6,5,4,3,2,1     | int16/uint16       |       |
| #L  | 1,2 or 1,2,3,4,5,6,7,8    | int16/uint16       | Default byte order if not specified |
| #LL | 1,2,3,4 | int32/uint32/float | Default byte order if not specified |
| #LB | 2,1,4,3 | int32/uint32/float | |
| #BB | 3,4,1,2 | int32/uint32/float | |
| #BL | 4,3,2,1 | int32/uint32/float | |

#### .LEN\[H]\[L]

When the data type is STRING, .LEN is a required field, indicating the number of bytes the string occupies. Each register contains two storage methods: H and L, as shown in the table below.
| Symbol | Description                                 |
| --- | ------------------------------------- |
| H   | One register stores two bytes, with the high byte first |
| L   | One register stores two bytes, with the low byte first |

::: tip
The address data for the T C R region is six bytes.
The first two bytes can use bit or int16, uint16 types;
The middle two bytes of data need to be of type int16 or uint16, with the address suffix added .PRE;
The last two bytes of data should be of type int16 or uint16, with the address suffix added .ACC.
For example, T2:1.ACC
:::