Technical Library

Label Sensor Performance Comparison

Label Sensor TechNote (LT04-0041)

Copyright © 2015 Lion Precision. www.lionprecision.com

Label sensor performance is a measurement of how accurately the sensor detects the edge of the label and how that accuracy is affected by speed. Label sensor performance is one consideration in determining which sensor is best for you.

How accurately a label is located on a package is determined by many other factors like the mechanics of the machine and the other sensors responsible for detecting the package position. But label placement accuracy will never be better than the label sensor's ability to accurately locate the label edge.

Synopsis

Capacitive label sensors are far faster and more accurate than any other label sensor technology regardless of whether the label is clear or not clear.

The charts below show the label location (registration) of 240 consecutive labels as detected by different technology sensors. A single bar down the center indicates all 240 labels were accurately placed within ±.0.05 mm (0.002"). Other bars indicate how many label placements varied (how tall the bar is) and how far they varied (how far the bars are from the center of the chart).

Measuring Label Sensor Performance Accuracy

Registration accuracy is measured by recording outputs of the sensor (label detections) and comparing the timing of the outputs with known label edge locations. This test is performed on a specially designed machine with an encoder that precisely tracks label positions within one micron.

"Accurate" detections have less than ±0.05 mm (0.002") of error. The charted results show the number of accurate detections and the number of times the sensor output fell into 0.1 mm (0.002") error bands from the correct label edge position. The results are compiled from detection of 240 labels. The label webs used have 3 mm (0.125") gaps.

70 m/minute = 230 feet/minute

220 m/minute = 720 feet/minute

Reading The Label Sensor Accuracy Charts

Sample Label Sensor Accuracy Chart

Ultrasonic Label Sensor 70 m/min Ultrasonic Label Sensor Accuracy Chart 220 m/min

Ultrasonic (LRD8200)

Ultrasonic sensors have a great advantage of detecting the broadest range of materials. But they are the least accurate of all label sensor technologies. Their accuracy is directly related to web speed – accuracy continually decreases as speed increases.

Choose an ultrasonic sensor when you want to be sure you can detect any type of label and you can tolerate the registration inaccuracies, especially at higher speeds.

Within ±0.1 mm @ 70 m/min: 25%

Within ±0.1 mm @ 220 m/min: 12%

The LRD8200 is an ultrasonic label sensor.

Capacitive Sensors

Capacitive sensors come in two configurations: Differential (LRD2100), and Single-Ended (LRD6300).

Capacitive sensors are extremely fast and accurate. They are perfectly accurate at all machine speeds. No other sensor technology can say that.

 

Single ended Capacitive Label Sensor Accuracy Chart

Capcitive Label Sensor Accuracy Chart 220

Capacitive - Single-Ended (LRD6300)

Capacitive label sensors are extremely accurate at all speeds.

Single-ended capacitive sensors work well with artwork that includes metallic stamps and metallic inks.

Solid foil label materials may be difficult to accurately detect with this type of label sensor.

Choose this sensor if accuracy is important and if you use clear labels and labels with metallic artwork but never use solid foil labels.

Within ±0.1 mm @ 70 m/min: 100%

Within ±0.1 mm @ 220 m/min: 100%

The LRD6110 and LRD6300 are single-ended capacitive label sensors.

Differential Capacitive Label Sensor accuracy chart70

differential capacitive label sensor accuracy chart 220

Capacitive - Differential (LRD2100)

Capacitive label sensors are extremely accurate at all speeds.

Differential capacitive sensors have extremely stable setups and require little adjustment.

Any metallic inks or other metallic materials will interfere with the sensors performance. Black inks with high carbon content and also be a problem.

Choose this sensor if accuracy is important and if you use clear labels but never labels with any metallic materials or metallic inks.

Within ±0.1 mm @ 70 m/min: 100%

Within ±0.1 mm @ 220 m/min: 100%

The LRD2100 is a differential capacitive label sensor.

optical label sensor accuracy chart 70

optical label sensor accuracy chart 220

Optical (LionEye2)

Optical sensors are perfectly accurate at low speeds. At higher speeds, their accuracy degrades a small amount.

Optical sensors cannot detect clear labels.

Choose this sensor if you never use clear labels.

Within ±0.1 mm @ 70 m/min: 100%

Within ±0.1 mm @ 220 m/min: 68%

The LionEye2 is an optical label sensor.

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