FAQs
Frequently Asked Questions – FAQs
How long is the calibration valid?
NIST recommends a one year calibration interval. Strainsert calibrations are traceable to NIST and valid from one year from the date of calibration. Strainsert lists the calibration expiration date on the product calibration sticker and/or the calibration certificate. An in- place calibration may extend this period if your internal quality requirements allow, see “re-calibration extended.”
Can the time for recalibration be extended?
Yes, by performing an in place calibration using a reference load cell, known load or other repeatable methods. You can establish a specific procedure that can be used to evaluate the performance of your sensor. Calibration extension should be included in your quality polices which dictate requirements for calibration extension in accordance with your measurement requirements.
What does in place calibration mean on my customer drawing?
The in-place calibration refers to the application of a known load to the transducer after being installed into the final assembly. Variations between the calibration fixtures and final assembly components can result in variations from the factory calibration data. An in-place calibration is recommended to quantify and account for these variations in order to optimize measurement performance.
What are the temperature limits of the transducers?
Typical temperature range is -40° F [-40° C] to 300° F [149° C] depending on the transducer type. The maximum limits, on case by case evaluation are -65° F [-53° C] to 400° deg. F [204°C]. Designs at these maximum limits may reduce overall performance and require special materials and/or components.
What linearity and repetition can I expect from a transducer?
Standard Force Products: Specifications can be found on our website for the various transducers.
Custom Force Products: Non-linearity, typically ±0.5 to ±2% full scale. Non-Repeatability: typically ±0.15% to ±0.3% full scale. Hysteresis: typically ±0.5 to ±4.0% full scale (Depending on type of sensor, design requirements and loading characteristics).
B-Axial Pins: Typically ±1% full scale on primary axis and a cross-talk correction algorithm is provided to improve accuracy of other positions. Typically less than ±5% full scale.
What is the resolution for Strainsert Transducers?
Resolution is a function of signal strength and output sensitivity. The output sensitivity varies with transducer design such as factor of safety and calibration load. The Strainsert calibration certificate data resolution is 0.5 micro-volt/volt of excitation.
What is the accuracy (precision) for Strainsert Transducers?
Strainsert does not state an “accuracy” for our products. Accuracy is a measure which defines how close the displayed reading of a sensor or sensor system is to a known standard. The system accuracy is dependent on the traceability of the standards used to calibrate the system.
Strainsert uses “Non-Linearity”, “Non-Repeatability” and “Hysteresis” as the measure of sensor performance. Strainsert defines these characteristics as follows:
Performance Characteristic and Description
Non-Linearity (NL): Measure of the maximum delta between the sensor output signal and the best-straight-line through 0 force to full scale capacity.
Non-Repeatability (NR): Measure of the maximum delta between the sensor outputs when measured repeatedly at the same applied load.
Hysteresis (H): Measure of the maximum delta between the sensor outputs when measured at the same applied load in the ascending and the descending loading directions
Note: All characteristics are expressed as a percentage of the full scale sensor output.
Many customers view the total accuracy as the root mean square of the non-linearity, repeatability, and hysteresis.
+/- Error = √ NL² + NR² + H²
What is the Response Time for Strainsert Transducers?
Research has demonstrated that the response time of foil strain gages have a response time up to 300 kHz for smaller 3mm gages, and up to 110 kHz for 10 mm gages. Strainsert transducers use grid sizes of approximately .125 to .25”. Therefore, we would estimate a response time between 110 to 300 kHz. Strainsert has not completed any testing to determine response time.
Why does the sensor zero move (change in the unloaded reading)?
The zero moves in all types of transducers. Overloads, impact loading, material relaxation, exposure to high temperatures, fatigue loading, or off axis loading may cause a zero shift. However, changes in zero do not typically change the span of the transducers. Therefore, the unloaded readings should be “nulled” out before each measurement use. If the span is changing, the transducers should be returned for evaluation.
Can the sensor withstand impact or vibration loading?
As a final check, Strainsert does a final product inspection, force calibration, and comprehensive electrical diagnostic checks. This final product checkout has allowed many of our customers to successfully use our products in impact and vibration environments with no reported issues.
Can we expedite shipping?
We try to offer our best lead time based on your design and production levels when quoting. We do understand that you may need it sooner. Reach out to our team to see if expediting is an option for your specific product. An advanced notice and current workload may allow for quicker turnaround. However, expedited ship schedule, if available, will require additional billing to the final invoice.
What is a standard lead time?
We do not have a standard lead time for custom solutions since there are so many factors that go into sensor design, however many of our custom applications can be completed in four to twelve weeks. Most of our standard products have a lead time of two to six weeks.
How can I get a copy of my calibration data?
We provide an online tool on our website where customers can look up and download their calibration certificates. Navigate to https://www.strainsert.com/products/custom-load-pin-configurator/ and follow the posted instructions to get your calibration data.
How do I return my parts for repair and recalibration, receive an RMA, or quote?
To receive an RMA and/or calibration quote, please complete our online RMA request form linked here: Strainsert Online RMA Request
Once submitted, you will receive a confirmation email with return shipping instructions, and a Strainsert Sales Representative will contact you shortly with your quote.
Contact the Repair Department at 610-825-3310 or by email to cu*************@********rt.com with any questions.