Smart data transfers and machine safety – have you taken advantage of the potential of metadata?

How is the safety data of your industrial automation? Are you getting enough timely data from your sensors? How could you add this to safe working practices?

Today, Ethernet-based field- and safety buses offer endless new opportunities for industrial data transfers. Sensors are capable of sending more than basic information, which is good news for machine reliability, operational safety and preventive maintenance.

Read on to discover the features and benefits of Ethernet-based safety bus technology in the 2020s.

In order to understand the basics of secure data transfers, we should go over the principles of the fieldbus and safety bus.

Fieldbus is a communication technology used in industrial automation to distribute digital data between devices and systems. Installing a fieldbus is an easier way of connecting different parts of machinery compared to hardwiring each device separately. Naturally, this makes for a faster and simpler installation process.

A safety bus is now commonly built inside the fieldbus to facilitate the transfer of machine safety data. As the name suggests, the purpose of the safety bus is to improve the safety of machine controls and management. The design of the safety bus must consider the appropriate and safe ways of using the machine and predict human errors and mechanical breakdowns.

Safety buses have developed by leaps and bounds in recent years. They are now safer, but also much smarter.

Previously, safety buses such as the AS-Interface Safety at Work largely operated with on-off functionality. They could indicate open safety devices but included rather limited sensor data. Typically, one message could only include the safety data of a single sensor, and only four bits at maximum.

Now the question is whether on-off indication is sufficient, or if the customer would like more device data for preventive maintenance and other purposes.

Modern safety buses use Ethernet-based solutions, which allow for many times the detail and volume of useful data. For example, sending fault data and deviations in variables to the control logic allows for accurate preventive maintenance – this type of data is called metadata.

Ethernet itself is not a next-generation technology, but it has been used in recent years to introduce a new dimension to automation. This has increased the versatility, reliability and safety of sensor solutions.

1) Less need for multimeters. Instead of maintenance technicians having to lug a multimeter to a machine, different data can be viewed directly from an office computer connected to the factory’s network, for example. In addition, reports can easily indicate if a fault has been detected.

2) Easier preventive maintenance through quick and seamless data reads. Collected data can be refined to aid in maintenance planning. For example, machine shutdowns can be scheduled based on detailed metadata to optimise the timing.

3) Better detection – and prevention – of machine operator errors. Common mistakes include accidental activation of emergency stop buttons that may halt an entire production line. By installing a suitable bus, the status of the button can be communicated quickly and supervisors informed if the press was a human error or an actual emergency.

4) Multiple improvements to operational safety.

For example: 
⦁ Predictive detection of safety device faults. 
⦁ Detailed information for operators about the root cause of a fault. 
⦁ Continuous automated safety device monitoring can indicate safety component failure via the bus in advance, unlike passive components.

5) Increased sustainability of machine use. Estimates suggest that up to 80 per cent of process industry sensors are replaced prematurely. Better diagnostics of sensor metadata can indicate the actual life cycle of a sensor. 

Smart data transfers can improve the usability of industrial automation and the targeting of maintenance, as well as safety, reliability, sustainability and cost efficiency, by reducing the unnecessary replacement of components.

As sensors provide more useful data, we can improve the execution and scheduling of preventive maintenance.

As we discuss modern safety buses, we should also ask what a sufficient response time is.

For a safety bus, the response time must be shorter than the time needed to stop the connected machine. The design must take into account the total machine response time and stopping times.

The target response time can be determined according to the needs of the production line, the process stage and safety factors, for example.

Data with a long permissible response time (not used to control the machine or process) can be transferred to a cloud, for example, and retrieved outside the factory network to collect data such as line functionality or production volumes. 

The target response time should find a balance between good usability and sufficient speed.

Data requiring a short response time (machine control data) cannot be sent to a cloud because the response time is simply too slow. It would also raise questions about the information security of process controls. 

• The option to add multiple components to a network via bus accelerates deployment because the devices can be simulated beforehand, for example.
• Special care is required to design safe controls for wirelessly operated machines. For example, only pre-defined manual controls are allowed for the controllers of personal overriding three-position manual safety devices. In other words, automatic functions must be blocked. Therefore, the wireless safety device must continuously indicate that it is functioning and within range while line of sight is maintained with the controlled device.

• Ethernet-based safety buses enable next-generation data transfers and multiply the amount of data.
• Metadata brings valuable opportunities: Sensors can provide useful data for preventive maintenance, for example.
• Response times must be designed for good usability and safety.
• New solutions also enable wireless operations. 

Take control of smart transfers – with the help of Sarlin

Our modern industrial environment benefits from smart, time-saving and cost-efficient data transfers. Sarlin provides expert assistance and products and components from the best manufacturers to raise your automation system’s data collection and use to the next level.

Our solutions:

• Expert consultation and support for industrial data transfer design and implementation.
• Smart sensor solutions and products for industrial data transfers.
• We operate independently of any device manufacturers – we are free to choose the best, most trusted brands as our partners.
• All our product partners are committed to our Supplier Code of Conduct, in addition to the required EU agreements.

Sarlin automation solutions

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