A common question at Morehouse we are frequently asked involving our 4215-meter load cell meter is if there is a performance difference between the standard 4215 load cell meter and the 4215 Plus.
Previously, we decided to make a video to show the upgraded stability of our 4215 HS load cell meter versus our standard 4215. That video shows the new high stability model under a short time by about 0.00003 mV/V, while the older model varied by 0.00006 mV/V.
That video can be found here.
For this article, we decided to take things further and test a standard 4215 indicator versus our newer 4215 Plus indicator.
We hooked up each meter to a load cell simulator and captured roughly 22,000 data points at the 2 mV/V setting on the simulator.
We decided to evaluate the meter best; we would look at the minimum and maximum readings, take the difference between these two points, and compare the average and the standard deviation.
Question: What is the difference in performance between the 4215 Plus and the standard 4215 load cell meter?
Unlike the video, which showed a 2x visual improvement on using the 4215 Plus (same stability as the HS), the 4215 Plus outperformed the 4215 Standard by a factor of 3 in most scenarios.
When we compared the largest deviations of the 22,000 readings between the 4215 Plus load cell meter and the 4215 Standard, there was an improvement of 3.6 to 6.67 times, depending on the filter settings.
Comparing the standard deviation of all the readings, often known as a Type A repeatability contribution to measurement uncertainty, showed an improvement of 2 to 3 times better when using the 4215 Plus.
In addition to being at least twice as repeatable, the 4215 Plus load cell meter is a standalone unit that does not require additional software, load tables, or computers to use the B coefficients and solve for Force.
It can store coefficients used to predict load cell deflection values throughout the calibrated range.
The polynomial equation, fitted to calibration data using the least-squares method, is found on many ASTM E74, ISO 376, and other calibration certificates.
Many other indicators use a span calibration, which introduces significant bias (Measurement error) because the load cell output often fits a calibration curve better.
Sometimes, the bias from a calibration span is larger than the load cell specification.
The bias adds additional error and increases the measurement uncertainty.
This means the 4215-load cell meter has far less bias than other meters that do not use coefficients.
Most indicators use span points, which means they try to draw or segment a line, and the results often result in additional errors that range from 0.01 – 0.1 % of the actual force value.
Morehouse has a paper explaining the differences between polynomial equations and span points.
The paper titled “Converting an mV/V load cell signal into Engineering Units: Why this is the most accurate and cost-effective way to use a calibration curve” can be found here.
The summary shows entering higher order coefficients into the 4215 Plus, resulted in an improvement of up to 2413 %.
In addition to reducing bias and improving repeatability, the 4215 Plus load cell meter can store 28 load cell calibrations.
With the 4215 Plus, calibrations are performed in mV/V and converted via the polynomial equation to various force units such as gf, lbf, kgf, kN, N, and t.
Any time the unit is sent in for calibration, a new polynomial equation is calculated and entered directly into the indicator.
This means additional adjustments are not needed, which reduces calibration costs.
Conclusion Comparing Morehouse 4215 Load Cell Meters
The 4215 Plus is a significantly more accurate meter than its predecessor. The data speaks for itself on the improved performance, equating to about a 3 x improvement.
For more insights into force and torque calibration, metrology, and load cell reliability, explore our comprehensive blog at https://mhforce.com/blog/.
We believe in changing how people think about force and torque calibration in everything we do.
This includes setting expectations on load cell reliability and challenging the "just calibrate it" mentality by educating our customers on what matters and what causes significant errors.
We focus on reducing these errors and making our products simple and user-friendly.
This means your instruments will pass calibration more often and produce more precise measurements, giving you the confidence to focus on your business.
Companies around the globe rely on Morehouse for accuracy and speed. Our measurement uncertainties are 10-50 times lower than the competition.
We turn around your equipment in 7-10 business days so you can return to work quickly, saving you money.
When you choose Morehouse, you're not just paying for a calibration service or a load cell.
You're investing in peace of mind, knowing your equipment is calibrated accurately and on time.
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# Load Cell Meters