Attachments are becoming increasingly important in the world of construction machinery and construction companies. Quickly changing „tools“ on construction machinery allows for a variety of different tasks to be performed with a single machine.
However, switching attachments from different manufacturers on a given construction machine usually presents users with unsolvable problems when it comes to digital data acquisition.
Not every attachment works digitally with the respective construction machine.
And what now?
MiC 4.0 provides the solution here...

The goal of Cluster 7 is to create a standard for cross-manufacturer communication between an implement and a construction machine. To this end, a data interface is to be developed that can map all relevant use cases for communication between the attachment and the machine. The focus is initially on the interface between the implement and the excavator.

The objective is not to standardize the existing mechanical, hydraulic, or electrical interfaces between the attachment and the construction machine, but rather to consider, based on existing systems, what data needs to be exchanged. This data includes identification data such as serial number and tool type, status data such as measured angular position, and control data for actuating tool functions, e.g., for a tiltrotator, as well as safety-relevant data, e.g., for the safe operation of quick couplers.

The first step towards this interface is the precise delimitation and definition of the interface between the attachment and the construction machine. For excavators, a cut through the dipper pin has been defined, so that the first quick coupler already counts as part of the attachment (see illustration).

Subsequently, use cases are defined, on the basis of which the data transferred at the interface is determined. At the same time, a manufacturer-independent architecture must be developed and tested.

This is supplemented by a safety concept and specifications for the secure use of the interface. Finally, all results of the cluster are to be summarized in a communication protocol that can be used by all manufacturers in their products.

As a basis, potential use cases for a data interface were identified by surveying the participants of the working group. The working group consists of representatives from the construction industry, attachment manufacturers, and construction machinery manufacturers, ensuring that a wide variety of perspectives on the subject can be considered. After collection, the use cases were prioritized.

Some exemplary use cases covered by the interface are:

• Tool identification upon coupling, so that information such as serial number, tool type, and manufacturer is available on the machine
• Setting up the construction machine for the tool, for example, automatic adjustment of required hydraulic pressure and volume for the tool
• Transfer of tax data from slew drives so that no additional HMI needs to be installed in the driver's cab
• Transmission of the tool's geometry data, which can be used, for example, to set workspace boundaries

Sub-clusters were formed to elaborate on the specific data provided through the interface. These sub-clusters, based on their respective competencies, deal with various topics. The sub-cluster of users from the construction industry contributes the requirements for the interface from the user's perspective. A sub-cluster of attachment manufacturers defines which data is required for the function of the tools and what tool information can be provided. In the quick coupler sub-cluster, topics concerning the operation of quick couplers via the interface are considered separately, as this presents special requirements for function and safety.

One sub-cluster of machine manufacturers deals with the architecture required for the interface and considers how secure operation of attachments can be enabled via the interface. A sub-cluster of technical experts is concerned with the concrete definition and implementation of the communication protocol.

The sub-clusters work on their topics in two- to four-week sprints (see figure). The results are compiled and coordinated across the entire working group every six to eight weeks. This agile approach, with its parallelization of work, enables targeted and efficient working even within a large group.

To implement the interface, the cluster decided to design a CAN communication protocol. The use of CAN bus is widespread in construction machinery, ensuring easy integration of the interface into construction machinery and attachments. The MIC communication protocol, tentatively titled „MIC 4.0 BUS,“ will be developed based on SAE J1939 and prepared to transmit the interface data.

Initial functional tests of the interface were already successfully completed in April 2022. The goal is to present a demonstrator at bauma22 and subsequently release the first version of the protocol, which covers the most important use cases. The protocol will include provisions for later extensions, so that an updated version can be released by MIC 4.0 every one to two years.

A safety concept will be developed for the safe operation of the interface to enable safety-related functions, such as the operation of quick couplers, via the MIC interface. In addition, methods for quality assurance will be defined and further developed as the project progresses.

The initial tests of the interface were very successful and show the great potential of the MIC 4.0 BUS. After its release, manufacturers of construction machinery and attachments can incorporate the interface into their products. This offers the opportunity to develop universally applicable hardware and software, as the standardized interface requires less bilateral coordination.

For users, the interface allows for a freer selection of attachments and machines, as the MIC interface enables seamless cooperation between
MIC tools and construction machinery. This concerns both data exchange and the control of attachments, which are simplified by the interface. This also makes the installation and commissioning of tools easier, as fewer additional, tool-specific controls need to be fitted in the construction machine. In the context of the networked construction site 4.0, the interface also offers a manufacturer-independent, uniform tool data set, on the basis of which evaluations and management can be carried out. Thus, the MIC 4.0 BUS will provide further momentum to the digitization of construction sites and consequently enable further innovations.

The goal of the MIC 4.0 BUS is to create a standard for cross-manufacturer communication between an implement and a construction machine. For this purpose, an interface has been developed that covers all relevant use cases for communication between the implement and the machine.

The goal was not to standardize the existing mechanical, hydraulic, or electrical interfaces between the attachment and the construction machine, but rather to investigate which data needs to be exchanged. This includes identification data such as serial number and tool type, status data such as the measured angular position, and control data for controlling the tool functions.

The data interface is supplemented by rules for operating MIC 4.0 BUS attachments, the control and monitoring of quick couplers, and an overarching safety concept to ensure safe operation.

The interface described in this document was developed between 2019 and 2024 by Cluster 7 of the MIC 4.0 project, which consists of representatives from machine and implement manufacturers as well as end-users of the products. The joint motivation in its development was to create maximum customer benefit.