How to add IoT capability to existing systems: Part 2
17 January 2018
Part 1 of this article series demonstrated how using remote I/O modules from Brainboxes will add Ethernet connectivity to installed systems, allowing the release of data from old and existing machines. DesignSpark continues by demonstrating how device data can be placed on local corporate networks, highlighting solutions for Industry 4.0 monitoring and control.
The following demonstration will show how connecting Brainboxes remote I/O modules to everyday inputs and outputs found on factory production lines allows the data generated to be shared across the corporate network. This means data isn’t trapped at the local machine and can be viewed from anywhere within the network and integrated with other business data sources and processes.
The demo will also highlight how easy it is to retrofit existing systems controlled by PLCs, simply by using monitoring technology. PLC programmes are normally only available to the engineer who installed the device, making further access difficult. The idea isn’t to replace the PLC but work alongside it.
Lastly, the demo will show how Brainboxes software APIs can reside on low cost hardware such as a Raspberry Pi. The software collects and distributes data from the factory floor to the corporate network. Now, while Raspberry Pi’s make great controllers, they aren’t designed to withstand extreme environments. Brainboxes industrial hardware is designed to cope with tough environments, where temperature may range from -40 to +80°C, electrical power from 5 to 30VDC and machine inputs or outputs may be switching up to 30V to 1Amp. The hardware collects the data and sends it back to the Pi for processing, meaning the Pi can be conveniently located in a controlled environment of a server room.
How it was done
Brainboxes Industrial I/O modules can communicate using the industrial standard communication protocol Modbus TCP, making them ideal for communication with PLCs and other industrial equipment. The modules also include an RS-422/485 or an RS-232 port for interfacing to other equipment.
However, there are limitation to industrial protocols such as Modbus TCP:
• Security: Modbus TCP is an inherently insecure protocol, anyone on the network can listen to data sent and received over the network as Modbus TCP
• Authentication: Modbus TCP has no concept of authentication, anyone on the network can communicate with a Modbus TCP device
• Command Response Protocol: Modbus TCP communication occurs using the command response model where a client makes a request of the server and the server sends an answer. This means that the client has to constantly poll the server to get the latest information. This process is highly inefficient and the clients’ data is old the second it arrives.
• Max number of connections: Modbus TCP devices have a maximum number of simultaneous connections which makes them inadequate for system where many clients wish to view the data
This is where modern internet communication protocols come in, such as TLS (Transport Layer Security), JSON (JavaScript Simple Object Notation) and WebSockets. They provide the following advantages:
• Security: TLS 1.2 is the current most secure encryption protocol (as of July 2016) used for communication on the open internet. It is used to secure everything from bank transactions to Facebook logins
• Authentication: there are many standards for authentication which allow a client to uniquely identification themselves with a server, so that both the client and server can be sure they are talking with an authorised peer
• Bi-directional real-time communication: using WebSockets once a connection has been established between client and server it remains open, allowing either client or server to instantly send data or commands to the other
• Max number of connections: WebSockets is a lightweight protocol allowing a controller such as a Raspberry Pi to maintain many hundreds of connections simultaneously
Industrial devices on the factory floor do not speak these protocols, so Brainboxes developed a suite of APIs which bridge the gap.
The demo
So how can you bridge the gap between industrial protocols and modern web protocols?
The following demonstration, hosted on the DesignSpark website and shown in the above video, will take you through this process, allowing you to retrofit existing machines with remote monitoring/control or create new machine panels using the latest technology while maintaining interoperability with existing industrial infrastructure.
Click here for details on setting up the demonstration and what skills and hardware are required.
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