How To Find Connection Points / Assembly Instance and Sizes for EtherNet/IP Scanner X-gateway Without EDS or Manual

28 Jun 2022

This Article provides details on how to obtain the required instances and correspondent sizes information for the EtherNet/IP scanner.

APPLICABLE PRODUCTS

AB7553, AB7668, AB7669, AB7670, AB7503, AB7524, AB7699, AB7957, AB7671, AB7672, AB7677, AB7678, AB7680, AB7673, AB7674, AB7675, AB7676, AB7679,

PRE-REQUISITES

Access to the IO device user guide

A PC, if using EtherNet/IP tool

Intro and overview

Setting up the EIP scanner from the webpage requires the EtherNet/IP adapter devices Assembly object (0x04) input and output instances to be entered. The scanner uses this to setup the connection for the IO data object (0x03). The scanner is configured for exact matching, meaning the assembly instance sizes need to be set correctly or the connection will fault.

Get Assembly Instance

The user guide for the IO device should include details on the EtherNet/IP IO assembly instances. Some devices my allow you to read the instances from a GUI, you may need to navigate though its menu to find the correct info.

The terminology used can get a little confusing varying among manufactures. On the EIP scanners configuration page we use the terms Originator > Target, Target > Originator, and config. A user guide will typically call them Output Data or Output Instance and Input Data or input instance.

It is useful to know that the terms are from the Networks perspective and Originator is the scanner and Target is the IO device. This means:

Originator > Target (Originator to target) = Output

Target > Originator (Target to Originator) = Input

Some device will provide multiple instances or different sizes depending on their configuration. It is important to ensure the assemblies used match the devices configuration.

If the configuration instance is not provided 1 can often be used.

Get Assembly Size

The size for the data object is typically in the user guide along with the instance but can very depending on the configuration. If you are unable to locate the Size you may be able to read the size from the size attribute (0x04). This assumes the size attribute is supported by the object.

This can be done with a get data request with a EIP tool such a EIPscan or an external EtherNet/IP Scanner tool.

The request will be with Service code 0x0E (get data) to object class 0x04 Attribute 4. Set the instance for the one you need to check. Keep in mind the data bytes are swapped. A response of AABB can be converted to decimal as BBAA. In the following example the response has CC 01 which converts to 460.