The Top Industrial Sensor Questions We Field (& Their Answers)

When it comes to advanced sensor technology, the biggest question we ask is, "What's not to love?"

That should come as no surprise.

They're sophisticated & constantly evolving to meet the demands of application. They're versatile and help devices and their operators do their jobs effectively. And they're complex.

However, these same traits (and many others) can leave some room for confusion or a need for clarification.

There are some questions about our advanced sensor technology that come across our desks more than others. And we're always happy to answer them.

To that end, we've created a list of the most common industrial sensor questions and, of course, their answers.

12 Industrial Sensor Questions We’re Frequently Asked 

The only bad question is the one unasked.

Here are the top questions potential and current customers regularly ask us:

(Click each question to jump to its answer)

1. What Contaminants Should I Be Concerned About for My Humidity & Gas Sensors?

2. How Do I Select the Right Sensor for My Application?

3. Can You Explain the Various Sensor Communication Protocols?

4. What is the Difference Between Absolute Vs. Gauge Pressure Sensors?

5. What's the Difference Between a Single-Channel and Dual-Channel NDIR Sensor?

6. What's the Difference Between NTC Vs. PTC Thermistors?

7. My Device is Battery Powered. Will That Be an Issue?

8. How Do I Calibrate My Sensor?

9. I'm Using a T9602 Harsh Environment Humidity & Temperature Sensor. How do I Communicate With it?

10. When it Comes to Thermistors, What is a Beta?

11. What is a Thermistor Resistance Table?

12. How do I get an Industrial Advanced Sensor from Amphenol?

1. What Contaminants Should I Be Concerned About for My Humidity & Gas Sensors?

For as sophisticated as advanced sensor technology can get, they are not 100% immune to the ill effects of contaminants on their functionality.

When it comes to humidity and gas sensors (think CO2, O2 sensors), there are a few contaminants to be aware of for their design and application:

1. Volatile Organic Compounds (VOCs): Many gas sensors, especially those designed to detect specific gases, can be affected by VOCs which might cause cross-sensitivity errors. These compounds include chemicals like solvents, cleaning agents, and hydrocarbons which can be emitted from paints, lacquers, and building materials.

2. Dust and Particulate Matter: Particles in the air can clog or cover the sensor elements of both humidity and gas sensors, leading to slower response times and inaccurate readings. Regular cleaning and maintenance are required to ensure reliable performance.

3. Corrosive Gases: Sensors exposed to corrosive gases such as chlorine, hydrogen sulfide, and ammonia may degrade faster. These gases can corrode the sensor elements or lead to the buildup of films on the sensor's surface, which impairs its function.

4. Moisture: Excess moisture can be particularly harmful to gas sensors. It can lead to condensation on the sensor surface, which might cause short circuits or erroneous readings. In humidity sensors, extended periods of condensation or frost can permanently damage the sensor by altering the properties of the materials used within them.

2. How Do I Select the Right Sensor for My Application?

The answer to this one can get pretty deep, and we suggest talking to an advanced sensor engineer about your specific needs.

Whether you're looking for a sensor to measure temperature, gasses, pressure, humidity, or any other metric, in general making this decision comes down to a few key factors:

• The application itself
• The environment the sensor will operate in
• The temperature range the sensor is expected to measure within
• The level of reading accuracy needed
• How quickly it needs to take readings
• The kind of packaging/housing the sensor needs
• Its circuit design
• Output type -- analog or digital

Keep in mind, these are just starting points. And again, it's best to speak with your sensor manufacturer about your project.

3. Can You Explain the Various Sensor Communication Protocols?

Absolutely!

• BACNET is a standardized method for enabling various building automation and control systems, including sensors, to communicate and share data efficiently within a networked environment.

• I2C (Inter-Integrated Circuit) is designed for low-speed peripherals to connect to microcontrollers or processors in a multi-master, multi-slave configuration. This protocol allows for packet-switched communication in a single-ended, serial bus format, using addresses to manage communications among multiple devices.

• Analog Outputs provide a continuous signal that varies to represent different physical measurements. These outputs are common in sensors, reflecting the magnitude of a measured parameter directly as an electrical signal, such as voltage in relation to temperature, making it easy to interface with analog input devices.

• Modbus is a communication protocol developed by Modicon, now Schneider Electric. It's widely applied in industrial environments for client-server communication between devices, offering simplicity in deployment and maintenance across various types of networks.

• CANbus (Controller Area Network) is a robust communication standard that allows devices and microcontrollers within vehicles or industrial systems to communicate without a host computer. It is notable for its high-speed communication capabilities, reliability, and sophisticated error handling.

• LINbus (Local Interconnect Network) serves as a cost-effective serial network protocol used predominantly in automotive applications for managing communication between components. It acts as a simpler alternative to CANbus, handling less complex tasks like control of windows, mirrors, and seats, and operates over a single wire with speeds up to 20 kbps.

4. What is the Difference Between Absolute Vs. Gauge Pressure Sensors?

To get right to it:

Absolute Pressure Sensors: These sensors measure pressure relative to a perfect vacuum. Essentially, absolute pressure is the total pressure at a point, measured from zero or vacuum. This measurement type is crucial where accurate pressure readings are necessary regardless of atmospheric changes, such as in scientific research, high-precision manufacturing, or when measuring barometric pressure and altitudes.

Gauge Pressure Sensors: Gauge sensors measure pressure relative to atmospheric pressure. This means the sensor's reading adjusts according to the changes in the ambient air pressure. This type of measurement is ideal for applications where the interaction with atmospheric air is critical, such as in pneumatic systems and fluid tanks that are open to the atmosphere. Gauge pressure readings can vary with the weather or altitude, as they're dependent on the atmospheric pressure at the measurement site​.

5. What's the Difference Between a Single-Channel and Dual-Channel NDIR Sensor?

In short:

Single-channel NDIR CO2 sensors use one wavelength to measure CO2 and are suited for environments that regularly return to baseline CO2 levels, like classrooms or auditoriums.

Dual-channel NDIR CO2 sensors, on the other hand, utilize two wavelengths, which allows them to maintain accuracy by using one wavelength as a reference.

Further Reading:  NDIR CO2 Sensors: Single- Vs. Dual Channel In HVAC Systems

6. What's the Difference Between NTC Vs. PTC Thermistors?

To answer this one, we'll have to get a bit granular.

Let's first take a quick look at how each functions and their applications.

1. NTC Thermistors: This thermistor type sees its resistance decrease as the temperature increases. This negative correlation means they're sensitive to temperature changes, especially in colder conditions.

   They are commonly used in applications where precise temperature measurement or control is required, such as in electronic devices, automotive sensors, and medical devices. They help in monitoring electrical circuits to prevent overheating and are used in rechargeable batteries to monitor charge status and temperature.

2. PTC Thermistors: This thermistor type increases its resistance as the temperature increases. PTC thermistors are often used as self-regulating heating elements and as over-current protectors in circuits. They are effective in applications like hair dryers or space heaters where preventing overheating is crucial. They can also reset themselves as they cool down, unlike fuses which need to be replaced after one-time use.

So what's the difference?

NTC thermistors are used for more precise temperature measurements due to their sensitivity and quick response to temperature changes. PTC thermistors, however, are better for applications that need a sharp increase in resistance at a certain temperature to trigger a protective mechanism. 

NTCs are ideal for continuous temperature monitoring across a broad range, while PTCs are suited for safety-focused applications involving temperature thresholds.

7. My Device is Battery Powered. Will That Be an Issue?

To a large extent, only as much as you want it to be.

Yes, there are some applications where a constant power supply simply isn't available (think portable devices). Advanced sensor technology can be designed with the power budget in mind. Usually, it involves adjusting the device's power and measurement cycles to maximize lifespan within the available energy budget, but without compromising accuracy or reliability.

For your part, it's important to remember that no battery lasts forever and those powering your devices will eventually need replacement.

8. How Do I Calibrate My Sensor?

This one is a bit tricky to answer.

In a very general sense, advanced sensor technology shouldn't need recalibration -- especially if it's custom advanced sensor technology.

Why?

Because it's been designed for the rigors of application, and by the time it could be considered due for recalibration, the sensor is likely at the end of its useful life and should just be outright replaced. In addition, sensor calibration -- especially in the field -- is difficult and requires a lot of controls to make sure that it's done correctly (something that's not always possible at the point of application).

However, there are exceptions to every rule.

Indeed there are sensors that can (and should) be recalibrated on a schedule. For instance, some sensors used in indoor growing applications need it after every growing season.

So where does this leave us?

It's best to talk to your advanced sensor manufacturer about the sensor technology you need, its lifespan, and its maintenance schedule.

9. I'm Using a T9602 Harsh Environment Humidity & Temperature Sensor. How do I Communicate With it?

We provide you with a ChipCap 2 Application Guide for your T9602 which can guide you through communicating with the sensor.

Need a copy of the guide? Get it here:

10. When it Comes to Themistors, What is a Beta?

A beta is a ratio that determines the slope of a resistance curve.

What's a resistance curve? Time for a little Thermistor 101!

A resistance curve for a thermistor is a graphical representation that shows how the resistance of the thermistor changes with temperature. This curve is essential for understanding and using thermistors because it helps predict their behavior in various thermal environments.

Here's a breakdown of what the resistance curve typically involves:

• Shape of the Curve: For NTC thermistors, the curve typically shows a steep drop in resistance as the temperature increases. Conversely, for PTC thermistors, the curve generally shows an increase in resistance as the temperature rises beyond a certain threshold.

• Temperature Coefficient: The curve illustrates the temperature coefficient of the thermistor, which is negative for NTCs (resistance decreases with an increase in temperature) and positive for PTCs (resistance increases with an increase in temperature).

• Calibration: The curve is used to calibrate the thermistor in practical applications, ensuring accurate temperature measurements or control. It allows for the conversion of resistance readings into precise temperature values.

• Sensitivity: The steepness of the curve at any given point can indicate the sensitivity of the thermistor. A steeper slope means higher sensitivity to changes in temperature at that specific range.

11. What is a Thermistor Resistance Table

Let's keep going with our Thermistor 101!

A resistance table for a thermistor is a detailed chart that lists specific resistance values at various temperatures. This tool helps you interpret a thermistor's resistance readings to derive the corresponding temperature measurements.

Here’s how a resistance table functions and why it's useful:

1. Tabulated Data: The table typically presents columns with temperature values alongside their corresponding resistance values. For each temperature point, there's a precise resistance value that has been determined through calibration.

2. Ease of Use: Instead of calculating temperature from resistance using complex equations or curves, users can directly look up or interpolate values in the table to find the temperature associated with a measured resistance.

3. Precision and Application: These tables are essential for applications requiring precise temperature control and monitoring. They help in avoiding errors that could arise from manual calculations or approximations.

4. Customization: Resistance tables can be tailored for different types of thermistors or specific application needs, providing data over the temperature range relevant to the specific operational environment of the device.

Your thermistor manufacturer should provide you with resistance table datasheets or technical documentation.

12. How do I get an Industrial Advanced Sensor from Amphenol?

That’s easy! Get in touch with us today: