Angular position sensor

Types of Angular Position Sensor

An angular position sensor detects changes in angle or rotational position. These sensors are often used in robotics for joint angle detection. However, their application cuts across different industries, such as automotive, industrial machinery, and consumer electronics. In the automotive industry, sensors detect the position of the accelerator pedal. In robotics, sensors detect the position of joints and limbs. Angular position sensors can be grouped into three main categories based on their working principles:

• Rotary Position Sensor

• Capacitive Position Sensor

• Inductive Position Sensor

Rotary position sensors are further divided into:

• potentiometric position sensors

• resistive position sensors

• Magnetic Position Sensors

• Optical Position Sensors

Rotary position sensors detect rotational movement around an axis, providing information about the angular position of a shaft or object. They are used in various applications, such as motor control, robotics, and industrial automation. Rotary position sensors use different technologies to detect rotation and provide position information. They include:

• potentiometers

• Hall effect sensors

• optical encoders

Capacitive position sensors measure changes in capacitance between the sensor and the target object. This section discusses the types of angular position sensors.

Specification and Maintenance of Angular Position Sensors

Angular position sensors come with different specifications that suit various applications. Here are some common specifications:

• Measurement Range

  Angular position sensors have a range that defines the maximum and minimum angles they can measure. The range can be up to 360 degrees (full rotation) or less, such as 0 to 90 degrees (limited rotation).

• Resolution

  Resolution refers to the smallest change in angle that the sensor can detect. Higher resolution means the sensor can measure angles with greater precision. For example, a sensor with 0.1-degree resolution can measure angles within 0.1 degrees of accuracy.

• Accuracy

  Accuracy is how close the measured angle is to the actual angle. It is usually given as a percentage of the measurement range. For example, a sensor with ±2% accuracy can have an error of 2% of the measured angle.

• Output Signal

  Angular position sensors use different output signals to communicate the measured angle. Common output signals include voltage (e.g., 0-5V), current (e.g., 4-20mA), or digital signals (e.g., SPI, I2C).

• Supply Voltage

  The supply voltage is the voltage required to power the sensor. Angular position sensors often use a voltage range of 5V to 12V.

• Environmental Protection

  Some angular position sensors are designed to withstand harsh environments. They have a rating for dust and water resistance (e.g., IP65, IP67). This ensures the sensor can operate reliably in dirty or wet conditions.

• Mechanical Mounting

  Angular position sensors have different options for how they can be physically attached to the system being measured. This includes the type of shaft or flexible coupling used to connect the sensor to the measured system, as well as the type of mounting brackets or adapters used to securely hold the sensor in place.

• Temperature Range

  Angular position sensors are designed to operate within a specific temperature range. This ensures the sensor functions correctly and reliably without being affected by extreme heat or cold.

Angular position sensors require regular maintenance to ensure accuracy and reliability. Below are some maintenance tips:

• Inspect the sensors regularly for signs of wear, damage, or contamination.
• Clean the sensors using a soft brush or a lint-free cloth. Avoid using harsh chemicals that may damage the sensors.
• Check the electrical connections to ensure they are secure and not loose.
• Inspect the mechanical mounting components, such as mounting brackets and adapters, to ensure they are not worn out or damaged.
• Follow the manufacturer's recommendations on the correct maintenance schedule and procedures.
• Perform functional tests to ensure the sensors measure angles accurately.
Inspect the sensors regularly for signs of wear, damage, or contamination.

How to choose angular position sensors

When buying an angular position sensor for retail, consider the following

• Demand

  It's important to buy sensors that are in demand. Research trends and talk to customers to find out what they need. This way, the stock will move.

• Quality

  Go for reputable suppliers who offer quality sensors. It's better to pay a little more for quality that lasts than to deal with returns and unhappy customers.

• Variety

  Stock different types of sensors to cater to various customers. Have contactless and mechanical sensors. Get sensors with different measurement ranges and resolutions. This way, every customer will find what they need.

• Price

  Consider the target market when pricing the sensors. Buy from wholesalers who offer competitive rates. There should be enough margins to make the profits move.

• After-Sales Support

  Choose suppliers who offer after-sales support. In case something goes wrong, the supplier should be able to assist. This will save time and money in the long run.

• Certifications

  Ensure the sensors have the necessary certifications. Look for CE, RoHS, and ISO certifications. These certifications show the sensors meet quality and safety standards.

• Stock Availability

  Check the supplier's stock availability. Can they provide the required quantities consistently? Choose suppliers who can meet the business's needs.

• Shipping and Delivery

  Consider the supplier's shipping methods and delivery times. Choose suppliers who offer fast shipping and reliable delivery. This way, the stock will arrive on time.

How to DIY and replace Angular Position Sensor

Position sensor replacement steps:

• Turn Off Power

  Before beginning any repairs or replacements, ensure that the power going to the position sensors is turned off. This will assist in preventing any accidental damage or short circuits from occurring as a result of live power.

• Identify the Sensor to be Replaced

  It is critical to determine which sensor needs to be replaced. This is done by inspecting the system and using the appropriate tools to compare the readings of the other sensors that are still functional.

• Disconnect the Electrical Connections

  Once the sensor has been located, the next step is to disconnect the electrical connections from the sensor. It is critical to note how these connections are linked so that they can be reconnected to the new sensor in the same manner.

• Remove the Old Sensor

  The old sensor is removed by loosening any screws or bolts holding it in place. Depending on the type of sensor, it may be necessary to use a wrench or screwdriver to do this.

• Install the New Sensor

  The new sensor is installed in the same position as the old one and is secured with screws or bolts. After that, the electrical connections are reconnected, following the notes made in step three.

• Calibrate the New Sensor

  Calibration is done to ensure that it is functioning correctly and providing accurate readings. This may involve using a calibration tool or following specific instructions.

• Restore Electrical Connections and Power

  After confirming that the new sensor has been calibrated correctly, the electrical connections are reconnected, and power is restored to the system.

Q&A

Q1: How do I know if an angular position sensor is faulty?

There are several signs that can indicate a faulty angular position sensor. These include erratic or incorrect readings of the angle of rotation, the performance of the system being affected (for example, in the case of the engine, the acceleration may be uneven), and warning lights on the dashboard (such as the check engine light). If any of these symptoms are present, it is advisable to check the angular position sensor.

Q2: Can I use an angular position sensor in harsh environments?

Angular position sensors can be used in harsh environments, but it is necessary to select a sensor designed for such conditions. For example, sensors with IP protection (Ingress Protection) against dust and moisture should be used in harsh environments with dust, water, or chemicals. Also, sensors with high or low-temperature resistance can be used in extreme temperature conditions.

Q3: What is the difference between absolute and relative angular position sensors?

Absolute angular position sensors measure the absolute angle of an object concerning a reference position that does not change, even if the sensor loses power or is moved. In contrast, relative angular position sensors measure the angle of an object concerning a variable reference that can change, which means they require a constant power supply and may need recalibration after power loss or movement.

Q4: Can an angular position sensor be used for linear position sensing?

Although angular position sensors are designed to measure rotational angles, they can be adapted to measure linear position in some cases. This can be done by using a conversion mechanism that translates linear motion into angular rotation, such as a lever or a rack-and-pinion system.