Thanks for your use of the MaxBotix Sensors. As such, Sara Damiano’s response regarding the 300mm reported value is correct. This is often caused by object defections or condensation. We offer a self-cleaning version of sensor that provides a more robust condensation solution. Link (https://www.maxbotix.com/product-category/all-environments/scxl-maxsonar-wr-products)
Should you have any further sensor questions, please let me know and I will be happy to help. The best way to contact us is at the following link ( https://www.maxbotix.com/contact.htm)
Scott Wielenberg
MaxBotix Inc.
techsupport@maxbotix.com
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