Industrial Sensing

The variety of specialized needs is amazing.  Even outside of truly extreme environments like mining, industrial equipment is still subject to severe circumstances that can cause failures if equipment is not designed, installed, and maintained with care.  Machinery in manufacturing production lines endures constant repetitive movements, vibration from motors and transport belts, and wear from the items being produced constantly moving through the equipment.  Process-based manufacturing in the chemical or pharmaceutical industries often consists of multiple stages, each of which could have temperature or pressure extremes, and use harsh chemicals.  Distribution environments employ various machines to enable storage and re-distribution of solid or liquid goods, and involve near constant use of pumps, conveyors, and vehicles to ensure timely delivery of goods.  Warehousing can require HVAC equipment to maintain very precise environmental conditions, and forklifts or robotic transports are constantly moving goods.  Finally, distributed and remote industrial installations are common, and these need to be able to endure very harsh temperature, humidity, and chemical environments.  Equipment installed in exposed metal enclosures can frequently endure temperatures from -40C to 70C as well as the associated humidity and airborne contaminants that are frequently found in installed environments. 

Sensors are frequently deployed in these environments to monitor machinery and give advance notice of failures.  For example, accelerometers can be used to monitor bearings in motors and other rotating assemblies and give warning when they might need to be replaced.  Temperature sensors are also advantageous for these scenarios, as they can help indicate when a motor is working harder than it is intended to, or a circuit is beginning to be overloaded.  In combination with humidity sensors, they can also warn when equipment is operating outside of its intended environmental range or materials are being stored outside of their environmental specifications.  Level and Pressure sensors are used to monitor liquid storage, transport, and usage systems, as well as being used to measure overload conditions and leaks in vehicle tires that could result in unsafe operation.  Even ambient light sensors have found a place in industrial settings, as they can be used to control lighting and other systems to provide energy savings and reduce operational costs. 

The data from all of these sensors can be used to drive efficient and successful industrial operations.  Run charts and other modelling methods can be leveraged to detect issues before they result in failures.  Safety is one of the most important factors that can be improved through the use of industrial sensors, as they enable monitoring of safety-critical parameters and can give pre-warning if a piece of equipment or the industrial environment is trending towards an unsafe condition.  Along with these early-warning benefits, documentation and control of an OSHA compliant workplace is another benefit that can be realized.  Cost savings can also be achieved through the smart use of industrial sensors, and manual labor costs represent one of the largest opportunities.  Instead of dedicating personnel to monitoring equipment and systems, those personnel can be used for higher value work in times when the sensors indicate that the equipment is operating normally.  The number of hours of work needed for scheduled maintenance can also be adjusted to actual need, thereby reducing labor costs and opportunity costs associated with equipment downtime.   Early warning of failure is particularly important in pharmaceutical, chemical, and other process-based industrial manufacturing.  In these environments, large amounts of money can be tied up in work-in-progress (WIP), and equipment failure can lead to large losses from scrap and lost revenue.  If any of the WIP is considered a hazardous material, the cost and effort of environmentally friendly disposal can magnify these losses even more.  The sum of these costs can present a significant burden, and highlights the critical need for sensors to help control and predict equipment failures.  In semiconductor manufacturing, for example, the total costs of a failure that stops the manufacturing process can exceed $1M.  Process inspection is another area where sensors play an important part.  If any portion of process manufacturing is out of spec, the entire lot may not meet final inspection criteria, and thus may need to be scrapped.  Sensors help ensure the process proceeds as intended and the quality of the end product meets specifications.  Finally, Energy savings can be realized through the use of occupancy, ambient light, and temperature and humidity sensors.  These can control lighting, HVAC, and other systems to minimize unnecessary use and make the most of natural light and environmental conditions. 

For these reasons and more, sensors have become an integral part of industrial operations.  How they are implemented, however, can have a huge impact on the ability of an organization to leverage their benefits.  Sensors that are fully integrated into systems can create reliability and uptime problems of their own if they fail.  For example, if a motor assembly has an integrated accelerometer that fails, it might be necessary to take the motor offline and shut down production while the sensor is replaced.  The net effect is that the reliability and uptime of the system is decreased, just as if the motor itself was much less reliable.  Integrated sensors can also leverage different communications medium, which increases the complexity and costs of monitoring systems.  The use of external sensors can mitigate these risks and provide enhanced ability of the system to monitor and predict future failures.  Since the sensors are no longer constrained by the systems they monitor, unified system of sensors can be used and advanced telemetry and management solutions become available.  This enables the use of new wireless technologies, which can reduce maintenance on the sensor system and enable more efficient operations.  Cloud-based monitoring can also be introduced, giving organizations the ability to increase efficiency of operations by managing maintenance operations from a single central facility.  Push notifications can also be set up for alert conditions, so that faults are noticed quickly without the need for an employee to constantly monitor equipment for proper operation.  One final benefit is that sanity checks can also be easily performed as a second sensor can be temporarily installed to verify readings and prevent unnecessary downtime. 

Fortunately, TI’s SimpleLink Multi-Standard SensorTag makes the addition of external sensors an easy, quick, and straightforward process, and a consistent wireless interface simplifies data collection down to a single, unified system.  The primary features of the SensorTag are outlined in Table 1.

Depending on the application, either Bluetooth Smart, ZigBee, or 6LoWPAN wireless technologies can be used on the integrated TI CC2650 wireless MCU, and the low power nature of each gives each SensorTag years of operation from a single coin cell, and 4MB of serial flash is present for offline data storage.  10 MEMS sensors are integrated into each tag, and extensibility is provided via DevPacks that can house additional sensors, actuators, or other enhanced functions.   To simplify the process of bringing up a SensorTag array, TI provides significant documentation and even supplies Android and iOS apps that greatly simplify deployment.  

Despite the low cost and high flexibility of the SensorTag, the components that make it up are very high quality.  TI leverages many of their own products to ensure that the tag provides reliable and accurate measurements, and the remaining sensors are also from top, trusted suppliers.  Infrared temperature sensing is provided by TI’s TMP007 MEMS thermopile sensor that can measure the temperature of an object without direct contact.  It features a reference temperature sensor, storage for calibration coefficients, and an internal math engine to provide very accurate surface temperature measurements.  TI’s HDC1000 digital humidity sensor is ultra-compact, but leverages internal temperature correction and a design that places the sensing element on the bottom of the package to provide high accuracy while remaining immune to environmental contaminants.  TI’s OPT3001 rounds out the integrated TI sensors and provides light sensing that is closely correlated to human vision from 0.01 lux up to 83k lux using the built-in full scale setting.  This allows a 23-bit effective dynamic range and very precise temperature measurements.  The other integrated sensors are also very high quality.  The altimeter and pressure sensor is a Bosch BMP280, a hermetically sealed absolute barometric pressure sensor with high EMC immunity and +/- 1m accuracy for differences in altitude.   An InvenSense MPU-9250 is used for precision multi-axis motion, rotation, and orientation sensing, and Meder’s MK24 ultraminiature reed sensor provides magnetic proximity detection.  Finally, a Knowles SPH0641LU digital MEMS microphone provides audio support while remaining very immune to cellular and analog interference.  For large deployments that require cost optimization on the SensorTag assembly, TI has provided full technical documentation including schematic and PCB artwork files, so that custom assemblies can be created that leverage only the required sensors.  Applications that require more functionality than what is pre-installed on the SensorTag can leverage the extensibility enabled from TI’s DevPacks.  These are custom-designed extensions designed for the SensorTag, and can be used to add additional sensors, displays, or actuators.  Several preconfigured DevPacks are available, as well as design files that enable efficient development of customized solutions.  

TI’s SimpleLink SensorTags have provided a revolutionary product for the quick and efficient deployment of industrial sensor arrays that can be used to augment or replace existing sensor installations.  The long life and wide range of sensors embedded within the SensorTag package ensure its compatibility with a wide range of sensing needs, and this is further augmented by its DevPack extensibility support.  When combined with a unified wireless interface and phone-based apps that simplify setup, a cloud based industrial sensor solution is now within the reach of any organization.