Next Low Temperature Sensor Configuration & Installation Guide

Overview

The Next® Wi-Fi Low-Temperature Sensor accurately measures temperature using a glass-coated platinum resistance temperature detector (RTD) encapsulated in a waterproof probe. This sensor has a one-meter (3-foot) lead, operates at extremely low temperatures, and withstands external condensation.

When measuring, the sensor momentarily energizes the RTD in series with a precision resistor, producing a voltage directly proportional to the RTD temperature. The sensor converts the analog voltage signal to a digital value and calculates the temperature.

Settings to Configure

The instructions to configure standard Next Sensor and Wi-Fi network settings are available in the Next Sensor Quick Start Guide. The settings below are specific to the Next Low Temperature Sensor:

Below—Temperatures measured below this value will cause the sensor to enter the Aware State.
Above—Temperatures measured above this value will cause the sensor to enter the Aware State.
Aware State Buffer—Prevents the sensor from bouncing between Standard Operation and Aware State when the readings are very close to a threshold.

For example, if you set a Maximum Threshold (Above) to 90° and a Hysteresis of 1°, once the sensor takes an assessment of 90.0° and enters the Aware State, it will remain in the Aware State until the temperature readings drop to 89.0°. Similarly, at the Minimum Threshold (Below), the temperature must rise a degree above the threshold to return to Standard Operation.

Calibration

The Next Low Temperature Sensor can be calibrated at any temperature, but it is ideal for calibration at 0°C. Calibrating further from 0°C may produce more accurate measurements at the calibration point, but less accurate readings when temperatures are not close to the calibration point.

Calibration Steps:

Place the temperature lead in a stable temperature environment (recommended 0°C).
Wait for the sensor to stabilize and get 2+ readings with minimal temperature change.
Enter the actual temperature in the text box and press Calibrate.
Keep the sensor at a stable temperature until a Calibration Success/Fail message appears in the readings.

Sensor Scale Settings

To adjust the sensor scale settings:

Click the scale icon at the far right of the top menu in iMonnit.

With the Next Low Temperature Sensor, you can display temperature values in either:

Fahrenheit
Celsius

Installation Steps

Step 1:

Follow the installation and setup steps in the Next Wi-Fi Sensor General Information Guide.

Step 2:

Configure the sensor's settings and scale information in iMonnit for your specific application or use case.

Step 3:

Route or place the lead as needed.

Troubleshooting

Symptoms

Detailed Problem Description

Solution

Hardware Error is Reported in iMonnit

The sensor base can't communicate with the measurement circuitry. STS is set to 2.

This condition is caused by the lead temperature being out of range of the sensor (-40°C to +125°C) or by an internal hardware failure. If this condition occurs all the time, try setting default configurations. If a hardware error occurs occasionally, move the temperature lead into a room-temperature environment. If the problem persists, contact Monnit Technical Support for further guidance.

Calibration Failed is Reported in iMonnit

The previous calibration or temperature reading failed.

Before calibrating the sensor, ensure it is in a stable environment (recommended at 0°C). Ensure the sensor lead is at a constant temperature by ensuring at least two reported measurements are stable (within 0.5°C of each other). A faster Heartbeat is useful when calibrating to ensure the temperature stays consistent.

As an alternative to setting a faster Heartbeat, power cycle the sensor and perform the calibration within the span of the typical 10 test messages that occur every 30 seconds in the first five minutes after the sensor is powered on.

With these conditions met, the calibration should be successful. If the problem persists, contact Monnit Technical Support for further guidance.