SmartSense equipment is rigorously tested and calibrated to be very accurate. Depending on the use case you may experience inconsistent temperature readings between SmartSense devices and built-in equipment displays. This guide provides best practice for placement and recalibration to ensure consistent monitoring.
Use these links to jump to your specific device.
SmartSense B Sensor Calibration
SmartSense Probe RT Calibration
SmartSense Smart Shield Calibration
SmartSense Smart Shield Pro Calibration
SmartSense Smart Guard Calibration
SmartSense HC Probe Calibration
SmartSense – Sensor Accuracy and Placement of a Wireless Z Sensor
SmartSense B Sensor
SmartSense B Sensors are generally installed inside refrigerated/cold holding equipment.
When comparing our SmartSense B Sensor temperature reading with another device for the purpose of verifying accuracy, there are several factors that will come into play. The first would be the placement of the B Sensor. If they are in different locations within the freezer/refrigerator, you would receive different readouts. The other factor is response time, meaning that if a comparison is made during the day when warm air is entering due to the door opening, our device and the internal device most likely won't respond at the same rate because they measure differently.
SmartSense B Sensors are NIST certified for accuracy (+/- 1ºF) and each sensor goes through a 5 point accuracy check to prove the spec on each device; all of which is completed before shipping to the end user.
The OEM built-in refrigerator/freezer probes are typically located in the back right or back left corner of the unit itself, which is where ambient air directly blows. For all food service operations, the FDA Model Food Code 2009 states that the placement of temperature probes should be near the warmest section of the refrigerator/freezer, which is typically closest to the door seal.
Model Food Code Regulations 4-204.112 Temperature Measuring Devices. (A) In a mechanically refrigerated or hot food storage unit, the sensor of a temperature measuring device shall be located to measure the air temperature or a simulated product temperature in the warmest part of a mechanically refrigerated unit and in the coolest part of a hot food storage unit. (FDA Model Food Code 2009)
SmartSense Probe RT
The SmartSense Probe RT thermometer communicates directly with the SmartSense app.
The FDA doesn't have strict documentation listed on how often restaurateurs and others in the food service industry should be calibrating thermometers. However, the FDA and local board of health regulations do have set rules on time and temperature specifications for every type of food that is served to the public. Because of this, HACCP principle 3 speaks directly to maintaining critical limits to which thermometer calibration applies.
It's important that thermometers are calibrated to measure within (+/- 2ºF) of the actual temperature being monitored.
The need to calibrate thermometers will be different in each HACCP plane, as it depends on how often the food temperatures are checked within the operation. For example, some businesses should calibrate daily, whereas others may only need to calibrate weekly.
SmartSense Probe RT calibration/verification should occur within your operation's established HACCP policies and procedures.
When to Calibrate
The need to calibrate thermometers will be different in each HACCP plan, as it depends on how often food temperatures are checked. Some businesses will calibrate daily, whereas others may calibrate weekly.
In addition, your SmartSense Probe RT should be calibrated/re-calibrated under the following conditions:
Calibrating a Probe
HACCP: Verification should occur within your operations established HACCP policies and procedures.
The following instructions demonstrate the proper calibration procedure for your SmartSense Probe RT. Food temperatures must be checked throughout the food preparation process, and the thermometers used must be accurate.
SmartSense Smart Shield
The SmartSense Smart Shield is a wireless K-Type thermocouple designed for recording temperatures throughout the flow-of-food process: receiving, preparation, cooking, holding, serving, and cooling.
Calibrating Your Smart Shield
The verification procedure is used to calibrate the thermometer probe such that it reads the correct temperatures. This calibration is accomplished through the use of ice water, which is approximately 32ºF, with excellent reliability if prepared properly.
SmartSense Smart Shield Pro
SmartSense Smart Shield Pro uses the latest touchscreen Android device, along with a custom app and Bluetooth wireless temperature probe for recording temperatures throughout the flow-of-food process: receiving, preparation, cooking, holding, serving, and cooling.
Calibrating a Probe
The calibration procedure is used to calibrate the thermometer probe such that it reads the correct temperature. Calibration is achieved through the use of ice water, which is approximately 32ºF with excellent reliability if prepared properly.
SmartSense Smart Guard
The SmartSense Smart Guard is used to monitor the temperature of hot and cold equipment such as refrigerators, freezers, hot boxes, and storerooms. The Smart Guard can be used to read ambient air with the internal thermistor or be placed on the outside of a unit with an attached external thermistor placed within the unit to record temperature.
When comparing the Smart Guard temperature reading with another device for the purpose of verifying accuracy, there are multiple factors to be considered.
SmartSense HC Probe
The SmartSense HC Probe is a wireless Bluetooth temperature probe used for task management and temperature taking of food throughout the flow-of-food process.
Calibrating a Probe
It's important to properly calibrate your probe so that it reads temperatures correctly. Calibration is accomplished through the use of ice water, which is approximately 32ºF with excellent reliability if prepared properly.
SmartSense - Sensor Accuracy and Placement of a Wireless Z Sensor
This document outlines SmartSense's commitment to providing high quality and accurate temperature sensors, ensuring our customers have dependable data to support their decision making. It also describes how sensor location and accessories can affect the recorded temperature, with suggestions for achieving optimal results.
Accuracy and Calibration
Measurements are vital to nearly every discipline of science, and we depend on measurements to make informed decisions on the product or process being measured. While qualitative measurements, like those from a non-calibrated temperature sensor, may be capable of detecting changing conditions, there is no way to know how close the displayed value is to the true value. To uncover the quantitative accuracy of a measurement, a controlled calibration must be performed.
SmartSense has designed our general-purpose AC-TMP5PINDIN sensor to use Maxim Semiconductors DS18B20 digital thermometer. The DS18B20 has several features that make it desirable including, unique serial number, internal analog-to-digital conversion, and +/-0.5 °C accuracy from -10 °C to 85 °C.
SmartSense offers an independent calibration for our sensors, which we recommend for all customers, to provide quantitative evidence of the accuracy of our products.
There are two common types of calibrations offered in the United States: NIST traceable, and the more stringent, ISO 17025. At the heart of both calibrations types is an unbroken chain of calibrations between a standard held by the National Institute of Standards and Technology, and the device under test. The benefit of an ISO 17025 calibration is that an independent auditor has evaluated the facility, processes, equipment, documentation, and capability of personnel involved in calibrations. This added level of oversight increases confidence in the calibration results.
SmartSense offers only ISO 17025 calibrations for our AC-TMP5PINDIN sensors. Our sensors are calibrated at three points across the temperature range to ensure the product is performing as expected.
The preceding evidence is offered to support the accuracy claims of our products and provide our customers confidence in the measurements taken by our devices.
In order to obtain results representative of the monitored product, it is important to consider the sensor location within the conditioned space. If the sensor is placed improperly, near a blower vent for example, it may not provide a realistic representation of the overall space. In any conditioned space there is some amount of instability and non-uniformity, and those issues are more pronounced on the walls, floor, ceiling and door. According to a study by NIST, stability issues are also more pronounced in consumer grade equipment, compared to pharmaceutical grade equipment.
Variation in temperatures of a commercial fridge
For pharmacy customers, the FDA’s publication on Vaccine Monitoring and Storage recommends placing the sensor in the middle of the space. This placement recommendation aims to have the recorded temperature reflect the space where the product is being stored. Some refrigerator and freezer manufacturers include a local temperature display on their equipment, but that sensor is rarely located in the center of the space. For this reason, the temperature values obtained from a calibrated sensor located in the middle of the space are generally more credible than those provided the manufactures display.
Sensor Accessories - Buffer
Our sensors have a fast response time, and can either have a virtual buffer vial enable or physical buffer vial attached. The buffer damps minor fluctuations providing a more realistic representation of the conditions experienced by the product.
Our sensors read on a set interval (typically 5-15 minutes). The reading shown is that of the temperature taken at that time. If you’re comparing temperatures in between reading intervals there may be some variance.