EEIP.py - THE Ethernet/IP compatible Python Module

• Support of Explicit and Implicit Messaging

• Supports IO Scanner and Explicit Message Client functionality

• Object Library with CIP-Definined Objects

• Provides a simple way to access Ethernet/IP Devices without special knowledge about Ethernet/IP. Only few lines of code are required

Visit www.eeip-library.de for more informations and Codesamples

Table of Contents

1. Installation
2. Explicit Messaging
   2.1. Supported Common Services
3. Examples
   3.1. Usage of Implicit Messaging to Read and Write data to Rockwell Point I/O
4. Library Documentation
   4.1. Methods
   4.2. Properties

1. Installation:

pip install eeip

Requirements:

Python 3.9

2. Explicit Messaging

2.1 Supported Common Services

Appendix A of the Commmon Industrial Specifiction (Vol. 1) provides informations about the Explicit Messaging Services.
The following services are supported by the library:

• Get_Attributes_All - Service Code: 0x01
• Set_Attributes_All - Service Code: 0x02
• Get_Attribute_List - Service Code: 0x03
• Set_Attribute_List - Service Code: 0x04
• Reset - Service Code: 0x05
• Start - Service Code: 0x06
• Start - Service Code: 0x07
• Create - Service Code: 0x08
• Delete - Service Code: 0x09
• Get_Attribute_Single - Service Code: 0x0E
• Set_Attribute_Single - Service Code: 0x10
• No Operation (NOP) - Service Code: 0x17

3. Examples

All examples are available in the folder "examples" in the Git-Repository

3.1 Usage of Implicit Messaging to Read and Write data to Rockwell Point I/O

The Following Hardware Configuration is used in this example

Allen-Bradley 1734-AENT Ethernet/IP Coupler
Allen-Bradley 1734-IB4 4-Channel Digital Input Module
Allen-Bradley 1734-IB4 4-Channel Digital Input Module
Allen-Bradley 1734-IB4 4-Channel Digital Input Module
Allen-Bradley 1734-IB4 4-Channel Digital Input Module
Allen-Bradley 1734-OB4E 4-Channel Digital Output Module
Allen-Bradley 1734-OB4E 4-Channel Digital Output Module
Allen-Bradley 1734-OB4E 4-Channel Digital Output Module
Allen-Bradley 1734-OB4E 4-Channel Digital Output Module
IP-Address: 192.168.178.107 (By DHCP-Server)
This example also handles a reconnection procedure if the Impicit Messaging has Timed out
(If the Property "LastReceivedImplicitMessage" is more than one second ago)

from eeip import *
import time

eeipclient = EEIPClient()
#Ip-Address of the Ethernet-IP Device (In this case Allen-Bradley 1734-AENT Point I/O)
#A Session has to be registered before any communication can be established
eeipclient.register_session('192.168.178.107')

#Parameters from Originator -> Target
eeipclient.o_t_instance_id = 0x64
eeipclient.o_t_length = 4
eeipclient.o_t_requested_packet_rate = 100000  #Packet rate 100ms (default 500ms)
eeipclient.o_t_realtime_format = RealTimeFormat.HEADER32BIT
eeipclient.o_t_owner_redundant = False
eeipclient.o_t_variable_length = False
eeipclient.o_t_connection_type = ConnectionType.POINT_TO_POINT

#Parameters from Target -> Originator
eeipclient.t_o_instance_id = 0x65
eeipclient.t_o_length = 16
eeipclient.t_o_requested_packet_rate = 100000  #Packet rate 100ms (default 500ms)
eeipclient.t_o_realtime_format = RealTimeFormat.MODELESS
eeipclient.t_o_owner_redundant = False
eeipclient.t_o_variable_length = False
eeipclient.t_o_connection_type = ConnectionType.MULTICAST

#Forward open initiates the Implicit Messaging
eeipclient.forward_open()
while 1:
    print('State of the first Input byte: {0}'.format(eeipclient.t_o_iodata[8]))
    print('State of the second Input byte: {0}'.format(eeipclient.t_o_iodata[9]))
    time.sleep(0.1)

#Close the Session (First stop implicit Messaging then unregister the session)
eeipclient.forward_close()
eeipclient.unregister_session()

4. Library Documentation

4.1 Methods

Constructor def __init__(self)

Instantiation of the eeip class. The constructor doesn not need any parameters.

def register_session(self, address, port = 0xAF12)

Sends a RegisterSession command to target to initiate the session and to take the Session-ID for further use. address: address IP-Address of the target device port: Port of the target device (Default is 0xAF12)
returns: Session Handle

def unregister_session(self)

Sends an UnRegisterSession command to a target to terminate the session

def get_attributes_all(self, class_id, instance_id)

Implementation of Common Service "Get_Attributes_All" - Service Code: 0x01
Specification Vol. 1 Appendix A - Chapter A-4.1 - Page A-7 class_id: Class id of requested Attributes
instance_id Instance of Requested Attributes (0 for class Attributes)
returns: contents of the instance or class attributes defined in the object definition.

def get_attribute_single(self, class_id, instance_id, attribute_id)

Implementation of Common Service "Get_Attribute_Single" - Service Code: 0x0E
Specification Vol. 1 Appendix A - Chapter A-4.12 - Page A-20 class_id: Class id of requested Attribute
instance_id: Instance of Requested Attributes (0 for class Attributes)
attribute_id Requested attribute
returns: Requested Attribute value

def set_attribute_single(self, class_id, instance_id, attribute_id, value)

Implementation of Common Service "Set_Attribute_Single" - Service Code: 0x10
Modifies an attribute value
Specification Vol. 1 Appendix A - Chapter A-4.13 - Page A-21
class_id: Class id of requested Attribute to write
instance_id: Instance of Requested Attribute to write (0 for class Attributes)
attribute_id: Attribute to write
returns: value(s) to write in the requested attribute

def forward_open(self, large_forward_open = False)

The Forward Open Service (Service Code 0x54 and Large_Forward_Open service (Service
Code 0x5B) are used to establish a Connection with a Target Device.
The maximum data size for Forward open is 511 bytes, and 65535 for large forward open
Two independent Threads are opened to send and receive data via UDP (Implicit Messaging) large_forward_open: Use Service code 0x58 (Large_Forward_Open) if true, otherwise 0x54 (Forward_Open)

def forward_close(self)

Closes a connection (Service code 0x4E)

4.2 Properties

tcp_port

TCP of the Remote Device (Default is 0xAF12)

target_udp_port

Only for Implicit Messaging
UDP-Port of the IO-Adapter for explicit Messaging - Standard is 0x08AE

originator_udp_port

Only for Implicit Messaging
UDP-Port of the Scanner for explicit Messaging - Standard is 0x08AE

ip_address

IP-Address of the Ethernet/IP Device

o_t_requested_packet_rate

Only for Implicit Messaging
Requested Packet Rate (RPI) in ms Originator -> Target for implicit messaging (Default 0x7A120 -> 500ms)

t_o_requested_packet_rate

Only for Implicit Messaging
Requested Packet Rate (RPI) in ms Target -> Originator for implicit messaging (Default 0x7A120 -> 500ms)

o_t_owner_redundant

Only for Implicit Messaging
"1" Indicates that multiple connections are allowed Target -> Originator for Implicit-Messaging (Default: TRUE) For forward open

t_o_owner_redundant

Only for Implicit Messaging
"1" Indicates that multiple connections are allowed Originator -> Target for Implicit-Messaging (Default: TRUE) For forward open

o_t_variable_length

Only for Implicit Messaging
With a fixed size connection, the amount of data shall be the size of specified in the "Connection Size" Parameter.
With a variable size, the amount of data could be up to the size specified in the "Connection Size" Parameter Originator -> Target for Implicit Messaging (Default: True (Variable length)) For forward open

t_o_variable_length

Only for Implicit Messaging
With a fixed size connection, the amount of data shall be the size of specified in the "Connection Size" Parameter.
With a variable size, the amount of data could be up to the size specified in the "Connection Size" Parameter Target -> Originator for Implicit Messaging (Default: True (Variable length)) For forward open

o_t_length

Only for Implicit Messaging
The maximum size in bytes (only pure data without sequence count and 32-Bit Real Time Header (if present)) from Target -> Originator for Implicit Messaging (Default: 505) Forward open max 505

t_o_length

Only for Implicit Messaging
The maximum size in bytes (only pure data without sequence count and 32-Bit Real Time Header (if present)) from Originator -> Target for Implicit Messaging (Default: 505) Forward open max 505

o_t_connection_type

Only for Implicit Messaging
Connection Type Originator -> Target for Implicit Messaging (Default: ConnectionType.MULTICAST) Possible values: ConnectionType.NULL, ConnectionType.MULTICAST, ConnectionType.POINT_TO_POINT

t_o_connection_type

Only for Implicit Messaging
Connection Type Target -> Originator for Implicit Messaging (Default: ConnectionType.MULTICAST) Possible values: ConnectionType.NULL, ConnectionType.MULTICAST, ConnectionType.POINT_TO_POINT

o_t_priority

Only for Implicit Messaging
Priority Originator -> Target for Implicit Messaging (Default: Priority.SCHEDULED) Could be: Priority.SCHEDULED; Priority.HIGH; Priority.LOW; Priority.URGENT

t_o_priority

Only for Implicit Messaging
Priority Target -> Originator for Implicit Messaging (Default: Priority.SCHEDULED) Could be: Priority.SCHEDULED; Priority.HIGH; Priority.LOW; Priority.URGENT

o_t_instance_id

Only for Implicit Messaging
Class Assembly (Consuming IO-Path - Outputs) Originator -> Target for Implicit Messaging (Default: 0x64)

t_o_instance_id

Only for Implicit Messaging
Class Assembly (Consuming IO-Path - Outputs) Target -> Originator for Implicit Messaging (Default: 0x64)

o_t_iodata

Only for Implicit Messaging
Provides Access to the Class 1 Real-Time IO-Data Originator -> Target for Implicit Messaging

t_o_iodata

Only for Implicit Messaging
Provides Access to the Class 1 Real-Time IO-Data Target -> Originator for Implicit Messaging

o_t_realtime_format

Only for Implicit Messaging
Used Real-Time Format Originator -> Target for Implicit Messaging (Default: RealTimeFormat.HEADER32BIT) Possible Values: RealTimeFormat.HEADER32BIT; RealTimeFormat.HEARTBEAT; RealTimeFormat.ZEROLENGTH; RealTimeFormat.MODELESS

t_o_realtime_format

Only for Implicit Messaging
Used Real-Time Format Target -> Originator for Implicit Messaging (Default: RealTimeFormat.HEADER32BIT) Possible Values: RealTimeFormat.HEADER32BIT; RealTimeFormat.HEARTBEAT; RealTimeFormat.ZEROLENGTH; RealTimeFormat.MODELESS

assembly_object_class

Only for Implicit Messaging
AssemblyObject for the Configuration Path in case of Implicit Messaging (Standard: 0x04)

configuration_assembly_instance_id

Only for Implicit Messaging
ConfigurationAssemblyInstanceID is the InstanceID of the configuration Instance in the Assembly Object Class (Standard: 0x01)

last_received_implicit_message

Only for Implicit Messaging
Date and time when the last Message has been received