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Connecting Sensors

Connector Geek
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The size of the global sensor market has been predicted to rise to over $220 billion by 2027, a growth of nearly 7% per year. By way of comparison, the global connector market is currently less than a third of this size, although it too is experiencing healthy growth. There are several reasons behind the rising popularity of sensors, and they are not limited solely to a single industry. The manufacturing sector, along with the medical, automotive and consumer industries are all driving this growth in sensors.

Brad IO Block

Sensor technology is benefitting from the continued development in the electronics industry. Today’s sensors are both more capable and smaller than ever before. Modern semiconductors are enabling sensors to become smarter – instead of simply detecting a signal, these sensors have the power to process the signal, making them an active rather than passive component. The latest embedded vision systems are just one example of the growing sophistication of sensor technology.

With the potential of the sensor market, is it any wonder that the three largest connector manufacturers have made considerable investments in sensor technology over the last decade? TE Connectivity, Amphenol and Molex all boast sensor product divisions, alongside many of the more specialist manufacturers like HARTING and Phoenix Contact.

With the prospects of the sensor market looking healthy for some time to come, this appears to be a sound financial decision. However, there is also sensible technical thinking behind the connector companies joining the sensor world. The fact is that every sensor needs a connector.

Tried and Tested

For many years, the M-series of circular industrial connectors has provided an ideal solution for sensor connectivity. From the diminutive M5 connector to the large, multipole M23 and larger, these are offered by an array of manufacturers to a common standard. They are robust, often waterproof, and offer an important advantage that is hard to quantify – familiarity. Their common use across the industry makes them an easy solution for installers worldwide.

However, there are changes coming to how sensors are being connected. These changes are being driven by the power of the internet, and how it is affecting machine-to-machine communications. In the home, the Internet of Things (IoT) is changing how we use our household appliances. In the industrial world, the Industrial Internet of Things (IIoT) and Industry 4.0 has resulted in the smart factory – a facility that collects data that is shared across a network to help make decisions about day-to-day operations. Similar connectivity is being found in modern cars and wearable technology in the medical sector.

This machine-to-machine communication relies on sensors to provide feedback. Data is collected and then shared with the network. This means two key changes for sensors.

The first is that will simply be many more of them. This explosion in the number of sensors is forcing installers to rethink how sensors are being connected to the rest of the network. The second change is that sensors are now no longer passively collecting data, but are now forming key components in the network in their own right. This too means that the method of connection needs to change. Our recent interviews with Dean Donnelly and Jeff Barnes of Molex discussed some of the challenges that face installers in the industrial world.

All of this means that there are some new developments in the world of sensor connectors that will become more common in the near future. The traditional M-series connectors will be with us for some time, especially because of the amount already deployed in the field. However, there are some new names on the block.

IO-Link

We have written about IO-Link on DesignSpark recently, and there is an excellent article published by our US colleagues at Allied here, so I won’t go into too much detail. However, in summary…

IO-Link is a serial communication protocol that allows point-to-point connection of sensors and actuators that are commonly found on the factory floor. IO-Link is designed to integrate seamlessly with existing PLCs (Programmable Logic Controllers) that form the control layer of the modern factory. More importantly for installers, IO-Link uses a standardised approach that allows sensor manufacturers to provide easy installation.

For those connector geeks among you, IO-Link has adopted unshielded versions of the M connector. The ports on IO-Link devices use a variety of M5, M8 and M12 types that are frequently used as the connectivity for sensors, which considerably eases the burdens of hard-working machine builders.

Introducing MicroSAM™

One of the greatest challenges for installers is how to integrate existing equipment into these new networks. The value of equipment already in use makes it undesirable, let alone unaffordable, to simply rip out existing sensors and replace them with new technology. For these applications, there needs to be a way to convert old sensors into a format that is compatible with the new industrial solutions.

The Micro Sensor Adapter Module (MicroSAM™) is a new piece of hardware designed around a postage-stamp-sized printed circuit board (PCB). This module will provide the data interface needed to convert an existing sensor into a plug-and-play element, ready for installation.

The physical form of the module will be a 32mm x 32mm PCB, populated with the components to provide power filtering and signal conditioning for a wide range of analog and digital sensors. The connector interface has been standardised on the T1M family (208-5874) from Samtec, in either the 4, 6 or 18 pin configurations. Designed on a micro-pitch of 1.00 mm, the T1M is a latching wire-to-board connector that delivers the reliability needed for industrial and factory-floor applications.

Micro Sensor Adapter Module (MicroSAM™) is a new piece of hardware designed around a postage-stamp-sized printed circuit board (PCB)

Single Pair Ethernet

Single Pair Ethernet (SPE) is another system that we have written about before, but it is worth talking about again, not least because the two consortia competing to become the de-facto industry standard have not stood still. SPE has been designed to bridge the final few centimetres between the ethernet network and the device - in this case, a sensor.

The new Single Pair Ethernet (SPE) protocol seeks to replace the older serial communication systems with a unified Ethernet installation using smaller, compact connectors. SPE is not intended to replace the existing ethernet equipment in the field. There is such an enormous amount in existing infrastructure that supports traditional ethernet that this would be costly and time-consuming for little benefit. Instead, SPE is designed to take ethernet into places that it was previously unable to reach.

By converting the field level of the smart factory to be an extension of the existing ethernet equipment, it is possible to create a single unified network. Each sensor can be equipped with an SPE connector and given its own unique IP address, creating seamless communication from the machine to the cloud.

The SPE connector can also deliver power, removing yet another obstacle to installing a new device. Using Power over Data Line (PoDL), the SPE connector system can deliver the power of up to 50 Watts to the end device, which removes the challenge of providing a local power supply. All this is achieved with just a single twisted pair cable.

As a result, the SPE connector can be small and lightweight, making it an ideal connector solution for the new breed of miniaturized sensors. There are currently two alternatives for the connector. The SPE Industrial Partner Network has standardized on the HARTING T1 (203-9059) , whereas the competing SPE System Alliance has chosen a different design, typified by the Phoenix Contact solution. Both types comply with IEC 63171.

Harting SPE Connectors

Further Reading

If you are interested in finding out more about IO-Link, Single Pair Ethernet and MicroSAM, there is plenty of material for you to read. Take a look at this brief list, and keep checking here at DesignSpark - this is a topic that we are going to follow with interest...

MicroSAM - The PICMG webpage

The DesignSpark Engineer's Guide to SPE

A one-minute guide to IO-Link in action

Connector Geek is Dave in real life. After three decades in the industry, Dave still likes talking about connectors almost as much as being a Dad to his two kids. He still loves Lego too. And guitars.

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