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Temperature in API 6

Simple Hardware devices can measure temperature with various sensors and various precision. This article is about temperature in general and how to work with it in API 6.

Overview

Temperature encoding

Temperature in API 6 is encoded in SimpleTemp encoding. There are two sets of temperature values: true temperature and temperature hysteresis

In true temperature values, every hex value has an assigned temperature value from a range from -40°C to 87°C. Every hex value is 0.5°C higher than value n-1: e.g. 0x00 is -40°C and 0x01 is -39.5°C.

Temperature hysteresis values range from 0°C to 15.75°C where the difference between each value is ±0.25°C - these are used in temperature hysteresis downlink registers only.

Hot bit

You can use the hot bit (bit 1 of register 0x56) to shift the true temperature value range by +35°C (-5°C to 122°C instead of -40°C to 87°C) in case you need to e.g. detect fires.

The hot bit is one of the few exceptions to stateless features in the API 6 - more here!

Temperature functionality

  1. There are several temperature-based User modes: Temperature threshold alert (+ WiFi variants), Temperature change alert (+ WiFi variants), Temperature threshold alert with redundancy, Temperature change alert with redundancy, and Legionella mode. You can find an overview of all of these modes below.

  2. Temperature values can be sent as appended payload. If you have a SimpleIndustry with dual temperature probes, you can receive data from both the sensors using this feature.

    More about appended payload HERE!

  3. Two temperature-based independent alerts can be sent.

    1. Threshold alert - works like Temperature threshold alert, but independent
    2. Periodic temperature independent event - records temperature in a time interval and can send 1-9 records in one message

    More about independent alerts HERE!

User modes

Temperature threshold alert (+ WiFi variants)

Temperature is measured in a periodic interval. You can set up to three temperature thresholds and when either of those threshold is breached either way (up or down), you receive an alert.

Temperature change alert (+ WiFi variants)

Similar to the mode above, but there are no thresholds - a temperature delta (trailing threshold) is set up instead. For example - 3°C. First measured temperature is considered to be a starting point and if the temperature increases or decreases by 3°C, you get an alert. Once you get an alert, the delta threshold is moved and again, if the temperature increases or decreases by 3°C, you get another alert.

Temperature threshold alert with redundancy

Works exactly like Temperature threshold alert, but sends a pipeline of 5 temperature and 5 time bytes with every threshold alert. This allows you to have a backup of alert history in case the message are lost.

Temperature change alert with redundancy

Works exactly like Temperature change alert, but sends a pipeline of 5 temperature and 5 time bytes with every change alert. This allows you to have a backup of alert history in case the message are lost.

Legionella mode

This mode can work with either one or two temperature sensors and is intended to monitor temperature on water pipes to prevent Legionella bacteria from multiplying. The mode monitors a longer time interval and tells you the highest and lowest recorded temperature during this time interval and much more. Please see the mode details to get a full picture.

Relevant registers

Register hex Register name Value range What it is and what it does Useful for
0x1D Temperature threshold A SimpleTemp An alert is sent when this threshold is crossed either way. Temperature threshold alert modes, independent events
0x1E Temperature hysteresis A SimpleTemp If the measured value hovers around threshold A, it will be ignored until the difference is at least the hysteresis. Temperature threshold alert modes, independent events
0x1F Temperature threshold B SimpleTemp An alert is sent when this threshold is crossed either way. Temperature threshold alert modes, independent events
0x20 Temperature hysteresis B SimpleTemp If the measured value hovers around threshold B, it will be ignored until the difference is at least the hysteresis. Temperature threshold alert modes, independent events
0x21 Temperature threshold C SimpleTemp An alert is sent when this threshold is crossed either way. Temperature threshold alert modes, independent events
0x22 Temperature hysteresis C SimpleTemp If the measured value hovers around threshold C, it will be ignored until the difference is at least the hysteresis. Temperature threshold alert modes, independent events
0x2F Temperature delta SimpleTemp Delta that triggers the Temperature change alert event. Temperature change alert modes
0x34 Temperature measurement interval SimpleTime How often the processor wakes the sensor up and asks for data input - how often the sensor measures. All temperature events
0x4D Temperature detection delay SimpleTime How long should the change of sensor input last before the message is triggered or data recorded. All temperature events
0x56 (bit 1) Device presets (Hot bit) SimpleTemp All temperature values are shifted by +35°C. Used in industrial use cases where measuring high temperature is required. All temperature events
0x7E Periodic temperature reporting aggregation 1-9 How many temperature records are sent at once. Independent periodic temperature alert
0x7F Periodic temperature interval SimpleTime How often a temperature record is stored. Independent periodic temperature alert
0x80 Temperature delta for Flow1 SimpleTemp Specific for Legionella mode, please see the details of the mode. Legionella mode
0x81 Temperature delta for Flow2 SimpleTemp Specific for Legionella mode, please see the details of the mode. Legionella mode
0x82 Flow1/Flow2 configuration Two binary flags Specific for Legionella mode, please see the details of the mode. Legionella mode
0x83 Number of samples For Flow1/Flow2 Binary flags Specific for Legionella mode, please see the details of the mode. Legionella mode
0x84 Legionella reporting period SimpleTime Specific for Legionella mode, please see the details of the mode. Legionella mode