Remote temperature sensor

 

Declaration of conformity

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Download the declaration of conformity

Presentation

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The Remote temperature sensor is a LoRaWAN class A sensor that manages two different power supplies: one is external and may range from 9V to 24V, the other one is internal on the battery. It also incorporates an internal antenna.

The sensor includes a 5-metre temperature probe.

The Remote temperature sensor allows the measurement of temperature over a wide range of values. It can measure from -40°C to +90°C with a precision of 1°C.

The table below shows the precision for each range of temperatures:

Temperature range	Precision
[-40°C ; -34°C]	+/-1.5°C
[-33°C ; +9°C]	+/-1.0°C
[+10°C ; +37°C]	+/-0.5°C
[+38°C ; +64°C]	+/-1.0°C
[+65°C ; +82°C]	+/-1.5°C
[+83°C ; +90°C]	+/-2.0°C

The measurement step is defined in the minimum field of a frame.

The housing is compatible with the following DIN rail adapter:

For more information about the casing, please visit: www.spelsberg.com

Family code:

The family code of Remote temperature devices is: 50-70-043-xxx

Radio propagation

In order for the sensor to operate correctly, the number of obstacles should be limited in order to avoid excessive radio wave attenuation. It is also important to place the sensor as high as possible. The cable gland should be positioned downward.

Autonomy

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The information in the table below represents how long the battery can last. It is based on the default configuration at ambient temperature (+25°C) within the optimal operating range of the sensor via a LoRaWAN network (one uplink frame), when the spreading factor used is SF12.

The disposable battery has a 3.6Ah capacity, of which 85% is used.

Transmission periodicity	Battery life
1 frame/ 2 hours	12 years

Human Machine Interface

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The Remote temperature sensor has a buzzer that allows it to “communicate” with the user.

Once the device is installed, switch the power ON to start up the device. The buzzer rings until an association is made.

When the sensor is trying to associate with a network, it emits the following sound:

Once the association is completed, the buzzer makes the following sound:

A reed switch (or magnetic switch) is available. A magnet can be used to activate it and perform specific actions on the sensor (configuration, reassociation…).

• Configuration: "void" frames are sent every minute for 10 minutes.

Standard reports are disabled in this mode.

Configuration mode
Way to trigger it	One passage of the magnet near the reed switch or specific ZCL command
Way to stop it	Another passage of the magnet or specific ZCL command
Effects on the sensor
Duration	The configuration mode lasts 10 minutes

• A reassociation procedure can be requested if no downlink frame is received by the sensor during a given periodicity (4 days by default) or if a given number (100 by default) is reached or in case of failure (no acknowledgement received) by sending an applicative frame to the sensor or via the sensor’s IHM.

The sensor keeps the AppEUi and DevAddr configured, Confirmed/Unconfirmed configuration and all applicative configurations. However, LoRaWAN configurations (channel, data rate…) are lost.

ReAssociation Mode
Way to trigger it	Three passages of the magnet near the reed switch or ZCL command from LoRaWAN cluster.
Effects on the sensor

• A factory reset is available on nke Watteco’s sensors. It deletes all the applicative settings saved in the flash memory (i.e. configured batches and reports will be deleted).

The sensor keeps the AppEUi and DevAddr configured. However, LoRaWAN configurations (channel, data rate…) and applicative configurations are lost.

Factory reset
Way to trigger it	Two quick passages and a very long passage (until the sensor rings for the reset) of the magnet near the reed switch
Effects on the sensor

Applicative layer

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Codecs are available to decode frames: Downloads

The Remote temperature sensor integrates the following clusters:

Cluster	Cluster name	Managed attributes
0x0000	Basic	All
0x0050	Configuration	All
0x8004	LoRaWAN	All
0x0402	Temperature Measurement	All

Default configuration

A default configuration is set:

• The device reports the temperature every 2 hours (EndPoint 0 / Cluster Temperature Measurement / Attribute Measuredvalue).

Every change made to the default configuration must comply with the legal duty cycle (for example, the most restrictive in the EU is 0.1%, which corresponds to approximately 1 frame per hour with SF12)

Measurement periodicity

The measurement periodicity depends on the minimum and maximum recording intervals, and the delta.

If the value of the minimum and the delta is 0, then the maximum value is the periodicity. However, if the value of delta is different than 0, then the periodicity is 1 second.

If the value of the minimum is different than 0, then this value is the same as the periodicity.

Frame examples

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All frames have to be sent on port 125

Standard report

Report

 

Report of the temperature of the remote sensor

 

Configuration

 

Configure a standard report on the temperature

 

Batch report

• Configure a batch report on Temperature and Battery voltage:

Timestamp and record the temperature with a resolution of 0.1°C, a value has to be saved at least every 6 hours or on a variation of 1°C.

Timestamp and record all power source voltages with a resolution of 0.1V, a value has to be saved at least every 24 hours. All data have to be concatenated and sent every 24 hours at the most.

→The solution to concatenate several different physical values in the same frame is to use batch reporting. For the batch, the number of physical measurements that will be sent must be known in order to choose a label for each of them and the size of these labels. There is only 1 power source in the sensor (disposable battery). So with the temperature and this power source, it is necessary to manage 2 different labels.

Label number	Tag label	Tag size
1 or 2	0/1	1
3 or 4	00/01/11/10	2
5 or 6 or 7 or 8	000/001/010/011/100/101/110/111	3
...	...	...

The Tag Size to use for 2 labels is 1. Label 0 can be used for Temperature and Label 1 for level of Disposable Battery. To configure the batch, a command “Configure reporting” must be sent for each cluster.

For temperature, the delta has to be set to 100=0x0064 (1°C), minimum to 30=0x001e (30 seconds), the maximum to 6*60=360=0x8168 (6 hours), the resolution to 10=0x000A (0.1°C) and the tag to 0b00000001=0x01 (size 1 and label 0). The cluster to report is 0x0402 and the attribute 0x0000 (MeasuredValue).

For Disposable Battery power source the delta has to be set to 200=0x00c8 (0.2V), minimum to 10=0x800a (10 minutes), the maximum to 24*60=1440=0x85A0 (24 hours), the resolution to 200=0x0064 (0.1V), the tag to 0b00001001=0x0a (size 1 and label 1), the field to 4=0x04. The cluster to report is 0x0050 and the attribute 0x0006 (Node power descriptor).

Power sources (Bits field)	Description
0x01	Constant (main) or External power
0x02	Rechargeable battery
0x04	Diposable battery
0x08	Solar harvesting
0x10	TIC harvesting
Others	Reserved
0x00	Undefined: should not occur

Applicative payload of the temperature

 

Applicative payload of the battery voltage

 

To decode the batch reception, use br_uncompress. Type for Temperature is I16 (7) and for others the type is U16 (6), so the following command must be used:

echo "200200606025410d271ce80441ff9d230083ff6787f5b30f68b72cef9228" | br_uncompress -a 1 0,10,7  1,100,6

Result

DECOMPRESSION SERIES

cnt: 2   # Batch counter (from 0 to 7)

18450  # Timestamp in seconds of sending of the frame

# Format of data is: Timestamp of Measurement | Label | Value

811 0 2410    # Timestamp: 811 s     Label 0: Temperature                   Value: 24,1°C

841 0 2550   # Timestamp: 841 s     Label 0: Temperature                    Value: 25.5°C

911 0 -1250   # Timestamp: 911 s     Label 0: Temperature                    Value:-12.5°C

941 0 -1370   # Timestamp: 941 s     Label 0: Temperature                    Value:-13.7°C

12011 0 -1230  # Timestamp: 12011 s     Label 0: Temperature                    Value:-12.3°C

844 1 3700  # Timestamp: 840 s      Label 1: Disposable battery            Value: 3.7V

1444 1 3500  # Timestamp: 840 s      Label 1: Disposable battery            Value: 3.5V