Sensor Programming Services

Concord Sensors has extensive experience and tooling to program popular programmable Magnetic Sensors from any manufacturer. We use air core, Helmholz coils to assure accuracy and precision. We are able to provide small volume programming with reasonable setup fees and piece part test costs.

In the event you require programming or optimization of finished assemblies Concord Sensors can consult on fixturing for programming at our facility or for custom fixturing and programming hardware and software for your in-house production process.

Devices we program include:

• Melexis Switch, Latch and Linear Hall and Triaxis® Sensors: MLX90215, MLX90251, MLX90277, MLX90288, MLX90291, MLX90292, MLX90316, MLX90324, MLX90333, MLX90360, MLX90363, MLX90364, MLX90365, MLX90366, MLX90367, MLX90371, MLX90372, MLX92212, MLX92242, MLX92292
• Micronas HAL series devices
• Allegro Linear, Switch and Latch Sensors A1162, A1190, A1192, A1192-F, A1193, A1193-F, APS, 11900, A1340, A1341, A1342, A1343, A1346, A1356, A1357, A1377, A1377, ALS31313, ATS344, ATS128
• AMS Linear, Rotary and 3D Position Sensors AS5030, AS5040, AS5043, AS5045, AS5045B, AS5047D, AS5047P, AS5048A, AS5048B, AS5050A, AS5055A, AS5115, AS5130, AS5132, AS5134, AS5140H, AS5145A, AS5145B, AS5145H, AS5147, AS5147P, AS5161, AS5162, AS5170, AS5171, AS5172, AS5215, AS5245, AS5247, AS5261, AS5262, AS5270, AS5600, AS5601, AS5013, AS5304, AS5306, AS5311, AS5403, AS5410, AS5510, NSE-5310
• Infineon Linear Hall Sensors TLE4997A8, TLE4998C8D, TLE4998S8D, TLE4998S8, TLE4998S4, TLE4998P4, TLE4997E2, TLE4998C3, TLE4998C3C, TLE4998C4, TLE4998C8, TLE4998S3C, TLE4998P3, TLE4998P3C, TLE4997A8D, TLE4998P8, TLE4998P8D, TLE4998S3
• Asahi Kasei EQ950L Programmable Linear Hall Sensor and CQ series Current Sensors

Programmable Hall Sensors

What is a sensor? A simple answer might be a device which responds to a stimulus and converts that stimulus into a signal of another form. A compass is a sensor that converts a magnetic stimulus into a mechanical angle indicator. A spirit level (bubble level) gauge converts mechanical attitude to a visual indicator. But in their most useful form, sensors convert their stimulus to an electrical signal. Modern sensors are complex electronic circuits with many operational amplifiers, passive electronic components, microprocessors, RF communications circuits or TCP/IP or other wireline communications circuits.

Where is a sensor needed?

As soon as a control loop is established in a system there is a need to sense, a need to evaluate the sensed quantity and a need to make decisions based on the merits of the sensed values.

Magnetic Sensors

Magnetic sensors include many types of devices. From the simple, a pivot needle compass, to complex, a Superconducting Quantum Interference Device or SQUID for short. All magnetic sensors can sense magnetic fields generated from permanent magnets or from electrical current flowing in a conductor.

Hall Effect Sensors

One of the most successful and prolific types of magnetic sensors is the Hall effect sensor. Hall effect sensors typically are made from Silicon, although other semiconductor materials like Gallium-Arsenide or Indium-Antimony are also common. In its simplest form a Hall effect sensor could be a 4 terminal passive device requiring a bias current between 2 terminals and the measurement of the raw Hall voltages across the other two terminals. These simple sensors have been in high volume production for decades in optical disk drives, for example.

Since the early 1970’s Hall effect sensors have been constructed using typical Integrated Circuit fabrication processes. This allows the combination of the Hall Sensor with transistor amplifiers on a single chip. Early examples used bipolar junction circuit technology. Modern Hall effect sensors use Complementary Metal Oxide Semiconductor (CMOS) circuit technology. With CMOS, it is possible to combine sensors with sophisticated digital signal processing.

Hall effect sensors respond to magnetic field strength and polarity. This can lead to great flexibility and function in creating all manner of non-contact sensors for measuring speed, position, angle and electrical current flowing in a conductor.

Magnetic Sensor Types

Basic Analog-ouput Hall effect sensors simply provide an output voltage or signal (PWM, for one) that is proportional to the measured field strength and polarity. Newer sensors are beginning to support more advanced digital output protocols like SENT, SPI and LIN.

Basic Digital Hall sensors take the analog measured field strength and polarity and change their output state from logic 0 to logic 1 based on threshold conditions. These thresholds may be set by the circuit design, or they may be permanently trimmed at the factory.

Angular Position Sensors are more sophisticated devices that are responsive to the angle of the magnetic field rather than the magnitude. This is used for mechanical position sensors. The underlying technology may be standard Hall effect (Austria Microsystems), Triaxis Hall effect (Melexis), vertical Hall effect (Allegro Microsystems, Micronas), or Magnetoresistive (NXP)

Programmable Hall Effect Sensors

Programmable Hall effect Sensors are a relative modern invention. The first fully integrated devices were launched in the mid 1990’s by Melexis, Infineon, Allegro Microsystems and Micronas, each company at about the same time but with different circuit architectures and capabilities. Melexis, Infineon and Micronas offered fairly sophisticated analog or Linear hall sensors. Allegro Microsystems offered programmable Digital output devices for 2 wire and 3 wire operation. More recently, Austria Microsystems and Asahi-Kasei also released programmable sensors for specific position sensor and current sensor applications.

Such devices made it possible to build a sensor module (Hall effect sensor + magnet + mechanical components) then after assembly, potting and curing operations were completed apply a final calibration. In this way the accumulated errors from variations in magnet strength, molding tolerances, PCB assembly alignment, pick and place accuracy, and the effects of any gluing, soldering or other mechanical package stresses are minimized by setting the gain, offset, thermal drift coefficient and other compensation factors in nonvolatile digital memory.

The improved accuracy of calibrated sensors led to a rapid growth in Hall effect sensor applications. The investments in engineering and developing a programming process as an integral part of the manufacturing line are not trivial. As a result many manufacturers have yet to fully realize the promise of programmable Hall effect sensors.

Many electronic subcontractors offer IC programming services. This generally uses a standard interface (e.g. JTAG, SPI, I2C) to load a compiled binary file into the device. They may even use “bit-banging” to support non-standard digital interfaces for programming special devices. But they rarely are even aware of programmable Hall effect sensors and even less often will attempt to handle them. This is because the programming hardware, programming protocols and the need to include a mechanical or magnetic field control element in the programming cycle are beyond their scope. All programmable Hall effect sensors use proprietary interfaces – and each manufacturer is completely different.

In order to program Hall effect sensors it is necessary to be conversant with the protocols employed by the various manufacturers, there are no universal standards. Some manufacturers (Melexis, Allegro) will not even share the programming protocols with their largest cutomers. The user must use the programming hardware and software provided by the manufacturer.

Devices from different manufactures may have between 5 and 50 programmable parameters to support various features and calibration functions. Although most of the programmed parameters usually have similar functions, each manufacturer’s specifications use different reference terms.

Calibrating Sensors to a Magnetic Field Reference

When programming a single Linear Hall sensor apart from its assembly, it is necessary to generate a precise, calibrated, uniform magnetic field. This is not possible with permanent magnets, it typically requires an electromagnetic coil (or Helmholtz coil). Driving and controlling such a magnetic field requires high power, stable and precision power supplies. Then it requires a fixture to hold the sensor without damaging it while the sensor is properly situated in the uniform magnetic field. This just enables one to be able to set values at a room ambient temperature. Doing so over extended temperatures requires yet more engineering and fabrication of test fixtures. Of course Digital hall sensors can also be evaluated and programmed using the same systems as for analog output devices.

Calibrating Mechanical Position Sensors

Programming hall sensors in a position sensor module is challenging as well. Instead of calibrating the device to a reference magnetic field, the device is calibrated to a mechanical position. These sensors use a permanent magnet that moves with respect to the sensor. It’s necessary to mechanically actuate the assembly through its range of motion. Depending on the sensor, there will be a different transfer function and so necessarily a different algorithm to determine the best programming values. An efficient algorithm can solve for the best results with a minimal number of mechanical movements. In the ideal case, a sensor will be completely programmed after one movement through the mechanical range. This requires a thorough understanding of the sensors programming parameters and their interdependence. Without an optimized algorithm, it will be necessary to iterate the programming / movement several times. After programming, a second movement and measurement validates the completed unit.

Calibrating Current Sensors

Current sensors assemblies use a Hall effect sensor to measure the magnetic field produced by a current-carrying conductor (e.g. a copper bus bar). Some designs use a gapped magnetic core with a programmable linear Hall effect sensor in the gap. The current carrying conductor passes through the center of the core, so there is no loss. Because the core is made of a material with high permeability, the magnetic field is contained within the core, and the location of the conductor doesn’t have much effect on the current measurement. These sensors may use a linear Hall sensor that was calibrated with a Helmholts coil, or the sensor assembly may be calibrated at the factory. Normally it is not necessary to calibrate these sensors in the field with the current conductor.

With some newer Hall effect sensors (like the Melexis MLX91206), it is possible to eliminate the core and just place the sensor near the conductor. Unlike the gapped-core sensors, this assembly will be sensitive to the mechanical position of the sensor and conductor. These sensors must be calibrated with the sensor and conductor together.