Reading Objects

The dnp3read.py script can be used to connect to a DNP3 outstation and request data objects based on specified classes. The script offers several connection and request options that allow you to customize your interaction with the outstation.

Target Format

The format for specifyinf a remote address to connect to is a little bit different this time:

<link_addr>@<host>[:<port>]

The <link_addr> is the DNP3 link address, and the <host> is the IP address or hostname of the outstation. The default port is 20000.

Requesting Object Groups

The -G option specifies the DNP3 object group number to request. This is an integer representing the group of data objects you want to retrieve. For instance:

Reading all octet strings (group 110)
$ dnp3read.py -t 1024@127.0.0.1 -G 110
[I] Connecting to outstation (1024) at 127.0.0.1:20000...
Data Objects:
├── Object(s): Octet string (Obj: 110, Var: 1) [Range: 8-10]
│   ├── Octet string [0]:
│   │   00000000:   00                                                .
│   │
│   ├── Octet string [1]:
│   │   00000000:   00                                                .
│   │
 ...
│
└── Object(s): Octet string (Obj: 110, Var: 5) [Range: 7-8]
    └── Octet string [7]:
        00000000:   48 65 6c 6c 6f                                    Hello

Requesting Objects from Data Classes

To read all objects from specific data classes, just specify the -class* option:

Reading all class1 object groups
dnp3read.py -t 1024@127.0.0.1 -class1
[I] Connecting to outstation (1024) at 127.0.0.1:20000...
Data Objects:
├── Object(s): Analog output event (Obj: 42, Var: 1) [Count: 1]
│   └── 32-bit without time [0]: (prefix: 7)
│       ├── comm_lost: False
│       ├── local_forced: False
│       ├── online: True
│       ├── over_range: False
│       ├── reference_err: False
│       ├── remote_forced: False
│       ├── reserved0: False
│       ├── restart: False
│       └── value: 1
└── Object(s): Octet string event (Obj: 111, Var: 5) [Count: 1]
    └── Octet string event [0]: (prefix: 7)
        00000000:   48 65 6c 6c 6f                                    Hello
-class0

Requests class 0 objects. The response will include objects from the following groups:

  • 1: Binary Input

  • 3: Double-bit Binary Input

  • 10: Binary Output Status

  • 20: Counter

  • 21: Frozen Counter

  • 30: Analog Input

  • 31: Frozen Analog Input

  • 40: Analog Output Status

  • 87: Data Set

  • 101: Binary-Coded Decimal Integer

  • 102: Unsigned Integer—8-bit

  • 110: Octet String

  • 121: Security Statistics

-class1

Requests class 1 objects. The response may include objects from the following groups:

  • 2: Binary Input Event

  • 4: Double-bit Binary Input Event

  • 11: Binary Output Event

  • 13: Binary Output Command Event

  • 22: Counter Event

  • 23: Frozen Counter Event

  • 32: Analog Input Event

  • 33: Frozen Analog Input Event

  • 42: Analog Output Event

  • 43: Analog Output Command Event

  • 70: File Transfer

  • 88: Data Set Event

  • 111: Octet String Event

  • 113: Virtual Terminal Event

  • 120: Authentication

  • 122: Security Statistics Event

Note

-class2 and -class3 request the same object groups as -class1