What is a puck/shim and do I need to use it?

Question: What is a puck/shim and do I need to use it?

Answer: A puck, otherwise known as a shim or load concentrator, is an object placed between the sensing area and load (like cheese between two pieces of bread) to ensure that the sensor captures 100% of the applied load if the contacting surface is larger than the sensor diameter and to reduce high pressure for point load applications. The applied pressure should be between 1 and 10,000 psi.  If the applied force is small, e.g. 30 grams, a puck should be used to reduce the area to achieve at least 1 psi. For applied loads that are high but have a very small area, a puck should be used to reduce psi to below 10,000. For best results, the loaded area or puck should be between 70% (a diameter of 0.263”, or area of 0.077in2 ) and 100% of the sensing area but can be reduced to achieve results as described above.  Plastic pucks are recommended, as they are pliable but will not deform. Tekscan offers peel-and-stick delrin pucks for purchase at our online store.

Example of a puck adhered to a FlexiForce A201 sensor.

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Is "110% of the maximum load" what a FlexiForce sensor can handle?

Question: Is "110% of the maximum load" what a FlexiForce™ sensor can handle?

Answer: Typically, the answer is "no". The mechanical properties of the different force range sensors are very similar. The polymer materials of which these sensors are composed will start to deform plastically around 10,000 psi.

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Why do I need to calibrate a FlexiForce sensor?

Question: Why do I need to calibrate a FlexiForce™ sensor?

Answer: Calibration is a very important step. There is a slight variance between sensors, which calibration corrects. When performed in an environment similar to that of the test environment, calibration helps improve repeatability and neutralize drift.

Refer to our Quick Start Calibration Guide for more details.

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What is the maximum period of not using a FlexiForce sensor before you have to recondition it?

Question: What is the maximum period of not using a FlexiForce™ sensor before you have to recondition it?

Answer: You should recondition the sensor if you haven't used it in 24 hours.  Please note that the more you recondition it, the better it should perform.

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How much error is induced if a FlexiForce sensor is not conditioned?

Question: How much error is induced if a FlexiForce™ sensor is not conditioned?

Answer: The error could be greater than the standard ±5% error if not conditioned prior to testing. You should always condition the sensor prior to use.

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Why do you need to condition a FlexiForce sensor?

Question: Why do you need to condition a FlexiForce™ sensor?

Answer: You should always condition the sensor prior to testing because the sensor's output changes the first few times it is loaded. By loading the sensor before your calibration, you will ensure that the sensor is producing repeatable results for your calibration and testing. It will also produce a repeatable drift curve. You can condition the sensor by loading it at 110% of your maximum load for a few cycles.

Refer to our Quick-Start Calibration Guide for more details.

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How do I connect a FlexiForce sensor after it has been trimmed?

Question: How do I connect a FlexiForce™ sensor after it has been trimmed?

Answer: If Tekscan trims the A201 sensors to two inches, four inches, or six inches, the sensor will come with three (3) male square pin connectors spaced at 0.1" (2.54mm). If you trim the sensor yourself, you will need to re-connect the sensor using one of two methods. You can purchase staked pin connectors and a crimping tool, or you can use a conductive epoxy to adhere small wires to each conductor.

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What is the resistance range of a FlexiForce sensor?

Question: What is the resistance range of a FlexiForce™ sensor?

Answer: The resistance range of the sensor is typically from  > 5MΩ at no load to approximately 5kΩ at full load. This can vary depending on the electronics being used to drive and read the sensor.

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What is the maximum recommended current for a FlexiForce sensor?

Question: What is the maximum recommended current for a FlexiForce™ sensor?

Answer: The maximum recommended current for the FlexiForce sensor is 2.5 mA.

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What drive voltages can I apply to a FlexiForce sensor?

Question: What drive voltages can I apply to a FlexiForce™ sensor?

Answer: 0.2V (as long as signal-to-noise (S/N) ratio remains acceptable) to 5V is the typical range.  The sensors output is also a function of the drive voltage/current therefore a constant voltage is recommended.

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