## 4 PicknPack Practice
### Demonstration and Evaluation  
The PicknPack production line was successfully demonstrated in Wageningen UR, Netherlands, and National Centre for Food Manufacturing, Holbeach, UK in 2016. It is a successful practice of IIoT manufacturing concepts integrating a wide spectrum of technologies by gathering the industry and academic institutes.  
In summary, the flexible M2M communications of PicknPack packaging line empowers the interactive collaborative operations between machines with the following advantages:  
* Easy connectivity, machine discovery and presence
* Convenient machine network run-time maintenance  
Figure 5: The PicknPack Food Packaging Line.  
* Ubiquitous messaging for events notification and data exchange
* Flexible system configuration and reconfiguration
* Cross-platform interoperability between machines
* Real-time machine interactions for collaborative operations
* Open to support high level interoperable functionalities.  
This M2M messaging mechanism is suitable for the collaborations of stationary industrial machines in a decentralised structure. Compared to those for lightweight self-organised ad hoc network or centralised infrastructure-based network, the strengths of the developed CoM2M lie in presence and discovery, ubiquitous messaging and machine understanding, which is well suited for IIoT manufacturing scenarios.  
With the CoM2M mechanism, machines can easily build a connection, and initialise themselves with configuration files. They can also conveniently initiate an event notification, data request, or data response in a flexible way. The whole line includes over 10 machines with LAN connection and the line moves forward in a speed of 7-15 cm/second. The size of JSON messages are in KB to MB. The latency of message is controlled in milliseconds in the operation of the system. The instant messaging and interoperable understanding between the machines gives them enough time to work on their manufacturing tasks.  
An example of M2M-based collaborative automation is the dynamic label printing of PicknPack food manufacturing, as shown in Figure 6. In the diagram, all modules (M1-M4) are notified the encoder position messages by the Thermoformer to identify the IDs of product packages in their workspaces, and perform their manufacturing tasks. The Pickrobot obtains the package IDs and link the information of raw food materials placed in the packages with the IDs. The QAS module obtains the package IDs and link the quality of food in the packages with the package IDs. When the Printing module identifies the IDs of product units in its workspace, it requests the source information from Pickrobot and quality information from QAS with the IDs, and then prints the information on product labels in real time. Therefore, the label printing operation is an interactive collaboration of four functional modules--Thermoforer, Pickrobot, QAS, and Printing with the underlying M2M messaging mechanism.  
Figure 7 gives the quantity and total size of messages received and sent by the machines performing the dynamic label printing task (M1-M4) in 1 min. The speed of messaging between machines is decided by the speed of manufacturing operations of the system. As shown in Figure 7, the QAS module receives and sends more messages than the peers since it coordinates five sensor machines and integrates their data to distribute to the machines of interest. For each machine,  
Figure 6: Machine Collaboration-based Dynamic Label Printing [26].  
the number of received messages are much more than it sent because of the heartbeat messages from the peer machines. All machines receive heartbeat messages from the peers in the industrial network.