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