top of page

Siemens S7 PLC EtherNet/IPTM 
Function Blocks

IO Scanner

Generic Ethernet Module

Generic CIP Message

EtherNet/IP converter

Siemens S7-1500 & S7-1200 PLC EtherNet/IPTM Implicit Message Class 1

Siemens S7-1500 & S7-1200 PLC EtherNet/IPTM Explicit Message UCMM

The EtherNet/IP IO Scanner Function Blocks will communicate
to all Ethernet/IP Adapters who support the "Generic Ethernet Module

Sigma has developed Function Blocks for the current Siemens S7 PLC S7-1500 & S7-1200 controllers to allow a S7 CPU to natively communicate with EtherNet/IP Generic Ethernet Adapter IO systems. These Function Blocks utilise the S7 PLC compatible CPU’s integrated Ethernet port or Ethernet Communications Processor with a programmed connection. The Produce/Consume model is employed by the EtherNet/IP IO Scanner - GEM Function Block.

This is the most integrated and powerful solution to connect directly to EtherNet/IP IO Adapters with a Siemens S7-1500 & S7-1200 PLC’s. The Sigma Function Blocks services the communication connection of all configured IO Adapters every PLC cycle. The IO update is based on the Adapter RPI. The RPI should not be less than the Longest PLC CPU cycle time.

ODVA is an international trade and standards development organization whose 300+ corporate members comprise the world’s leading suppliers of products and systems for industrial automation applications. The common interest of ODVA’s Members is the development and promotion of open and interoperable information and communication technologies for these applications. Sigma is a Licensed Vendor and Member of ODVA.

Siemens S7 PLC systems are products developed and distributed by Siemens AG Germany.

Siemens S7 EtherNet/IP IO Scanner

S7 EtherNet/IPTM IO Scanner - GEM

EtherNet/IP IO Adapter communication utilising "Generic Ethernet Module"

There are just three simple steps to achieve communications,

  • Call the IO Scanner “Generic Ethernet Module” Adapter EIPGEM Function Block in your user program

  • Prepare the Input, Output and any Configuration instances with the associated data lengths

  • Download to your S7 PLC CPU

The only requirement to configure your EtherNet/IP IO Adapter is to know its IP Address, the input instance number and data length, the output instance number and data length and any configuration instance information. Call the Sigma IO Scanner Function Block in you user program, no further programming is required as the S7 PLC becomes a native EtherNet/IP IO Scanner. The Function Block is licensed for a nominated S7 PLC CPU only, the licence is not transferrable.

The Produce/Consume model employed by EtherNet/IP CIP protocol specifies that all manufactured IO Adapters utilise fixed UDP Local and Remote Port numbers. The UDP Port numbers are reserved with the Internet Assigned Numbers Authority (IANA) for use with the EtherNet/IP encapsulation protocol and specifically in this case CIP Transport Class 1 message. The reserved Port number for EtherNet/IP IO Adapters on UDP is 2222. This concept of all Adapters using the same UDP Local and Remote Port numbers provides some difficulties as the S7 PLC and for that matter any other TCP/UDP compliant Ethernet device requires individual Local Port numbers to manage the data connection.

The Sigma Function Block parameters provide a freely selectable Local Port number. When only one IO Adapter device is connected to the S7 PLC this can be set to a Local Port number of 2222. When more than one Adapter is connected to the S7 PLC, a Layer 3 Router is required to provide UDP Source Port Forwarding. This can be simply achieved if your existing network infrastructure is suitable or a DIN rail mounted Router can also be utilised which just services the EtherNet/IP IO network.  Effectively the Router is just translating the Ethernet/IP Adapter’s Produce message Remote Port from 2222 to the configured Remote Port as specified in the S7 PLC Sigma Function Block Local Port setting. An entry in the Router Source Port Forwarding table is required for each EtherNet/IP Adapter in this instance. This methodology allows the Sigma Function Block to provide cyclic checks for the connected EtherNet/IP IO Adapters. This is a very important minimum requirement to provide equivalent PLC data updates. 

Siemens EtherNet/IP IO Scanner
Siemens EtherNet/IP IO Scanner

S7 EtherNet/IPTM IO Scanner - GCM

EtherNet/IP IO Adapter communication utilising "Generic CIP Message"

In addition to the Generic Ethernet Module Function Block, a Generic CIP Message Function Block is also supplied to allow the Get/Set of defined Object Instances that may exist in your EtherNet/IP IO Adapter. The typical use for this block is to read/write a parameter in a IO Adapter which is not a part of the cyclic IO data collected by the IO Scanner. Examples include setting an absolute encoders synchronisation position, read a Motor Protection Relays Over Current Trip level or reading a VVVF drive parameter setting.  


The Sigma EIPGCM Function Block provides the following features,

  • Explicit Unconnected CIP Generic Message

  • Data Types supported BYTE, SINT, WORD, INT, UINT, DWORD, DINT, UDINT, REAL and LINT (S7-1500).

  • Service Codes supported include Get_Attribute_Single, Set_Attribute_Single, Get_Attributes_All, Set_Attributes_All, Reset and Get_and_Clear

Siemens EtherNet/IP IO Scanner
Siemens EtherNet/IP IO Scanner


Please note you are purchasing a runtime only licence of the Sigma S7 EtherNet/IPTM IO Scanner communication Function Blocks, which are linked permanently to the initially nominated S7 CPU, the licence is not transferrable to another CPU.

Sigma S7 EtherNet/IPTM IO Scanner for S7-1500  & S7-1200 controllers.

Video - S7-1200/1500 Generic Ethernet Module - IO Adapter

Video - S7-1200/1500 Generic CIP Message

bottom of page