For more than two decades we've been supporting designers to incorporate our solutions into their products. Here are some of the most commonly asked questions about CambridgeIC - if you have a question that we don't answer below, please get in touch! If you have a CambridgeIC account, you can also access software and CAD downloads below.
1. What is CambridgeIC’s position sensing solution?
The moving part is identified with a target, and the position of the target is measured using a sensor built with conventional PCB processes. Positions are calculated by a specialist ICs (known as a CTU - central tracking unit) which can be located away from the sensor and target.
This arrangement means that CambridgeIC’s solutions have a number of advantages:
- highly accurate, absolute position measurement
- tolerant of misalignment and wide gaps
- durable with no performance degradation
- can be deeply integrated into product designs to offer significant cost savings
2. How does it work?
CambridgeIC position sensing solutions use resonant inductive position sensing to measure the position of a target. Sensor boards have an excitation coil and detection coils. For each measurement, the CTU drives a short burst of AC current into the excitation coil in the sensor, which in turn generates an AC field. The target attached to the moving part contains a resonator and the AC field will drive the resonator at its resonant frequency.
When the AC current is removed, the resonator will induce decaying EMFs in the detection coils. Their amplitude will vary, depending on the position of the resonator. By reading the amplitude of the EMFs from each detection coil, the CTU is able to calculate the position of the target.
Separating excitation and detection in time gives immunity from stray coupling between the excitation and detection coils. This produces superior sensor performance including more immunity to misalignment.
More details are available in the Technology section and in our CTU data sheets.
3. What is a CTU?
CambridgeIC’s Central Tracking Unit (CTU) chips are single-chip processors for position measurement. They implement the electronic processing for resonant inductive position sensing technology, and support a number of different sensor types, including rotary and linear.
CTU chips measure the position of contactless, inductively coupled targets relative to sensors that are built from printed circuit boards to CambridgeIC’s design.
4. Are CambridgeIC solutions affected by EMC fields?
5. Are CambridgeIC’s position sensors truly absolute?
6. Is the solution affected by metal nearby?
7. Will dirt or moisture affect the position sensor?
8. What is the maximum difference between target and sensor?
9. Can I use it in marine environments?
10. Is a CambridgeIC solution suitable for high volume applications?
11. How many sensors can be read by a single CTU?
CambridgeIC sells a range of CTU chips, differing in speed and the number of sensors that can be connected. That number depends on sensor Type (see ‘what are the differences between type 1, 2, 4 and 6 sensors?’), as below:
| :||Type 1 and 4 sensors||Type 2 sensor||Type 3 sensor||Type 6 sensor|
|CAM204||Up to 4*||1||1||2|
* a CAM204 chip using 3 or 4 basic sensors will require type 1 electronics, otherwise use type 4 electronics
12. What are the differences between Type 1,2,3,4 and 6 sensors?
|Sensor Type||Number of coils||Application|
|1 & 4*||1||2||Basic linear and rotary sensing|
|2||1||2||Long precision linear sensors|
|3||4||Linear sensors with target freely rotating around measuring direction|
|6||1||4||Precision linear and rotary sensors|
*Type 1 and 4 sensors have different electronics and connections – see data sheets for details.
13. How accurate are CambridgeIC position sensors?
|Max Linearity Error||Noise Free Resolution|
|Basic 25mm Rotary Sensor||±1°||11 bits|
|Basic 100mm Linear Sensor||±0.25%||10 bits|
|Precision Through Hole 35mm Type 6.3 Rotary Sensor||±0.2°||13.3 bits|
|Precision Through Hole 115mm Type 6.6 Rotary Sensor||±0.1°||15 bits|
|Precision 265mm Type 6.12 Linear Sensor||±0.05%||13.5 bits|
Figures are for operation at typical gap including typical installation tolerances. For a specific answer, please select a sensor and view its datasheet.
14. Are there any size limits?
Our sensor designs are for embedding inside products, and sizes reflect this.
The smallest standard rotary sensor is 21mm diameter.
The smallest linear sensor has a measuring length of 5mm.
The largest standard rotary sensor has a diameter of 115mm, with custom designs possible up to about 300mm.
The longest standard linear sensor has a measuring length of 500mm. We have done custom designs up to 2m.
15. How can I test the performance of a CambridgeIC solution?
The simplest way to get started with CambridgeIC solutions is to contact us with your design challenge and we can help you verify which sensor design would be most suitable. Development boards are available for all CTU chips, to help you characterise the performance of our solutions with your product in mind.
To simplify initial evaluation, a CTU Adapter is available to connect any Development Board to a PC over a USB port, and CambridgeIC CTU Software is available as a free download for configuration and viewing and processing measurement results.
16. How can I design CambridgeIC solutions into my product?
CambridgeIC has developed a range of standard sensor designs (including linear, rotary and arc sensors) which can be built using conventional PCB processes by any competent PCB manufacturer. We can supply PCB blueprints for your PCB designer, so sensor designs can be built into a board that can also support other electronic circuitry.
For prototyping we can also supply assembled sensors in low volumes.
17. I have a size/mechanical arrangement that is not covered by the off the shelf designs - can I get a custom design?