All,
You guys wanted an explanation about the MaxSonar sensor line calibration process. The calibration process does not require that an object be close (or far for that manner) from the front face of the sensor. It is just better (for most users) if the sensor is clear for the first 14-inches during calibration.
The reason for the calibration is twofold.
First, the ring-down pattern of the transducers can change from power-up to power-up (for various reasons), and so this calibration accounts for this.
Second, the calibration accommodates for most mounting arrangements. For example, say a sensor, on a robot, is mounted a few inches from the floor. For a normal ultrasonic range finder, the floor returns a very high reflection (and may cause a false detection). But for this MaxSonar sensor line, when the sensor calibrates, the sensor stores data for the first 14 inches. So in this example it calibrates itself to accommodate the reflection from the floor. This allows the sensor to ignore the floor. The sensor can do this because the floor is part of the stored ring down pattern. This is a very good feature for mobile robotics, and a very significant benefit to the sensor end user. In addition, one can mount the sensor back and even have some fixed nearby objects in front of the sensor and still have excellent operation.
Therefore, with all of the above, the calibration really does make the sensors perform much better for most users.
And, if an object is too close during the calibration cycle, the sensor may then ignore objects at that distance.
Can you send me the link or post the link to where you read this information. (We do not know of any of our sensors not working at their stated distances.)
The reason we believe that each sensor works at the distances specified on the datasheet is that each senor is calibrated at our factory (not to be confused with the power up calibration), to specified distances that ensures they match the beam patterns that are recorded in the data sheets. This calibration is unique to each sensor and is stored within the sensor’s firmware. This is in effect, a test of each sensor, but it is much more than a test. Each sensor is calibrated/verified to match the stated performance. An, EZ0, EZ1, EZ2, EZ3, EZ4, and WR1 all have repeatable part to part performance, factory calibrated and verified. This makes MaxBotix Inc., and the MaxSonar product lines stand out, because in the low-cost sensor market, MaxBotix Inc., makes this type of quality control its standard practice.
Whenever there is a problem that could be directly attributed to our sensors, we work very hard with the customer (they do have to email us or call us) to determine if the sensor are faulty or if the cause is some other source. If the anomaly is from the sensors, we correct it and give the customer, new (or corrected) products. If any users experience problems, we will replace the parts under warranty, with no cost to the customer. (We even pay for shipping.) Yet, the only way we can support our customers, is if they let us know they are having a problem.
If you have any further questions, please let us know.
Best regards,
Scott Wielenberg
Technical Support & Sales
of MaxBotix Inc.
Phone: (218) 764-2489 Ext. 2
Fax: (218) 764-2194
Email: scott@maxbotix.com
Web: www.maxbotix.com
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