Communication protocol? Wireless!

Today I would like to present You with an impression solution available on the market, which is a wireless communication protocol for industrial applications. This technology is operating at the drillship. Therefore this is a serious solution, not just an idea. So fast Your seatbelts, take Your coffee mug into your hand and let me introduce You to the advantages of wireless communication protocol.

Seadrill – West navigator

West Navigator is a 253m drillship. It has a frequent problem with a communication cable between the vessel and the driller itself. Brake of cable cost delay, which cost is around for 600.000 Euro per day. As You can imagine, even with a spare cable on board, this was not a simple operation to replace it onboard. A second very important topic is safety, no one likes to stop a drilling operation because of control failure. More of that, control failure cannot be rem. Due to a lot of movement of the cable chain, they faced wear and the cables broke after only a few months of operation so it causes failure.

The solution provided by the Schildknecht AG was based on their experience with industrial applications. They install their own devices. On the ship, a wireless PROFIBUS and PROFIsafe radio link on the driller. They use a communication protocol based on Bluetooth. Bluetooth is apply and thanks to frequency hopping it enable extremely stable and robust communication. The solution has to be adjusted to shipping and drilling requirements. An example installation required housings with ATEX proof.

So, how did this happen that this was possible to replace the control cable with wireless solutions?

Industrial communication over Bluetooth

But, let’s start from the basics. In standard solutions in the industry, data between PLC and I/O’s module ( Input/ Outputs) is delivered over the hardwired interface. Packets of signals from PLC are going to IO and the feedback is coming back to the PLC. The whole operation is looking like in the picture below. This is a reliable connection, but sometimes for different reasons, it is not possible to use a hardwired interface.

Data transfer over hardwired connections is going constantly. Therefore, there are no interruptions, until the cable will not be broken. The big problem with sending data over wireless communication is the delay, coming from the latency. For example, hardwired communication has a delay between 0.1 – 0.2 milliseconds. With radio communication, we have to be sure that the delay will not exceed. Stable connections are necessary to achieve reliable control. Above all, connections also have to be safe. Wireless protocols are always the weak spots. However, a solution that I will describe in detail today, solve issues with safety.

The longest response time in the system installed at the West Navigator is below 300ms. This is the boundary of the stable connection. How to be sure that our drilling operation or other important operation will not be stopped because of a missing data package. Here comes the solution

Solution of Schildknecht AG – Wireless communication

Schildknecht invented their own patent solution. The name of the device is Dataeagle. This is a smart radio system, which is processing the packages with extremely low delay. Patented algorithms check the data content, compare redundancy, and select the data which status change in the last cycle. This means that in every cycle, only data that changes is sent over the interface. This results in really low usage of the available bandwidth.

This is how this looks in practice. We have 4 cycles of operation. Each cycle takes 1ms. In the first cycle, complete data set of 8 signals are transfer between the PLC and I/O Module. For example, start sequence. I/O module confirms that the status gets changed. For example, the unit starts. In the next cycle, there is an interference of a connection. However, I/O Module is working on the previous data package. So small interferences are not breaking the operation. In the next cycle, the connection is free, because the Dataeagle module at PLC doesn’t register any changes in comparison with the previous packet. So Dataeagle at I/O Module is repeating the last known data package. Then we come to the last cycle when 1 from 8 data packages was changed. Only this data is sent between the PLC and I/O modules.

Security of the connection

Cybersecurity is very important at sea. Because Dataeagle uses their own protocol, the connection is safe, because communication is like in the tube. Dataeagle units are communicating only with each other. Dataeagle is operating on industrial Bluetooth. And as You can see, this solution is operating constantly on the 253m Drillship, and replace successfully a hardwired interface.

Conclusion

Solution Dataeagle is very clever. There is definitely a place for a special installation that can benefit from this solution. I would like to see how this communication works on board with the transfer of data between two compartments. To check if steel construction will interfere with the signals. However, the solutions is great, and can solve technical problems!

If You like to know more about the solutions, there are hyperlinks in the description!

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