Sentrius RS1xx LoRa-Enabled Sensors

There is no difference in appearance between external temperature sensor and RTD version of RS1xx. One way to tell them apart is by using Sentrius mobile app in which temperature threshold can be set wider range in RTD than in external temperature sensor. The external temperature allows from -40C to 125C, and RTD version of RS1xx allows for significantly lower and higher temperature measurements.  

Generally, LNS will only speed the sensor up via ADR while the sensor will only slow itself down. That is, if at a higher data rate and no answer is received, the sensor will gradually degrade its speed until a response is received from the LNS.

You can find TTN's latest codec for Laird's RS1xx LoRaWAN temperature & relative humidity sensor in https://github.com/TheThingsNetwork/lorawan-devices/blob/master/vendor/laird/rs1xx-temp-rh-sensor.js.

‘Open Dwell Time’ and ‘Close Dwell Time’ are times for how long an Open or Closed state must be maintained before a change to that state is announced.

While the temperature sensor included in RS1xx supports accurate temperature measurements across an operating temperature from -40 to 125C, the type of batteries installed in RS1xx can be a limiting factor. If using normal AA Alkaline batteries that have a recommended range of -18 to 55C, it may not perform well at operating temperatures above 55C.

When the battery capacity indicator shows a value of 2 (out of 5), this should be taken as a warning and the battery should be replaced soon. Once the battery capacity indicator decreases to a value of 1, the batteries should be replaced immediately. 

The sensor will operate down to a capacity of a value of 0, but the time for the battery capacity indicator to decrease from a value of 1 to a value of 0 will be much quicker than the time it takes for the battery capacity indicator to decrease from a value of 4 to a value of 3, for example.

Note: As the battery nears depletion, it can be expected that LoRaWAN communications may be intermittent or fail. 

Laird’s RS1xx LoRaWAN temperature & relative humidity sensor’s battery capacity indicator uses the following values for its battery capacity monitoring: 

0 = 0% to 5%

1 = 5% to 20%

2 = 20% to 40%

3 = 40% to 60%

4 = 60% to 80%

5 = 80% to 100%

If the remaining capacity is at a particular threshold (e.g., 5%, 20%, 40%, 60% and 80% capacity), it may result in reporting oscillating values occasionally. 

There are three ways you can power cycle RS1xx. 

1. Physically take out batteries and put them back into RS1xx.

2. Press Bluetooth button on the top of RS1xx for 5 seconds - both LED for Bluetooth and LoRaWAN should blink in green and blue when it takes the reset. 

3. Use downlink data when RS1xx is in Laird/Laird2 operating mode - refer to the RS1xx LoRa Protocol application note on RS1xx product page on Laird's website for more details. 

The JOIN EUI, formerly referred to as the "APP EUI" has been renamed by the LoRaWAN Alliance, as it identifies the Join Server. This EUI can be configured the same across multiple devices, to identify which specific join server the device is to be linked to. It consists of an EUI64, 64 bit (8 byte) identifier.

Because the JOIN EUI is configurable (can be modified) by the end user, it is not included on the packaging of the sensor. A default JOIN EUI is configured at the time of manufacturing. For standard RS1xx products, any sensor/sensor kit assembled after date code: 0223451 will be configured with the current Manufacturing JOIN (APP) EUI of ECC07A0000000006. Any sensor/sensor kit assembled prior to this will be configured with the previous Manufacturing JOIN (APP) EUI of F9C60ECEA3ADC6BD. 

The default JOIN EUI (APP EUI), can also be found in the RS1xx User Guide, section 4.1.1, or via the RS1xx Sentrius Sensor App available from the Google Play Store or Apple Store.

Additional information for this product can be found on the Sentrius RS1xx Product Page.

*Note: Custom RS1xx products have their own unique JOIN EUI and do not use the default JOIN EUI found in the User Guide.

The temperature sensor inside the Sentrius RS191 is the same as the Sentrius RS186 – so the information is the same for both SKUs.

The Integrated temp/RH sensor inside the Sentrius RS191 is based on the SiLabs Si7021-A20 integrated. Each SiLabs sensor is calibrated under controlled conditions which are traceable via accredited labs to standards set by NIST, the certificate of calibration from SiLabs can be found here; https://www.silabs.com/documents/public/miscellaneous/si70xx-calibration-certificate.pdf

The SiLabs part has a drift spec of <0.05C/year typical, as stated in the data sheet which can be found here; https://www.silabs.com/documents/public/data-sheets/Si7021-A20.pdf

No, the RS186/RS191 can only be used as a LoRaWAN end node with a LoRWAN gateway (concentrator) and LoRaWAN server.

It's important to note there are multiple RS1xx versions :

• Product Brief - Sentrius RS1xx Integrated Temp & Humidity Sensor
• Product Brief - Sentrius RS1xx External Temp Sensor
• Product Brief - Sentrius RS1xx with Open/Closed Sensor and Integrated Temp/RH
• Product Brief - Sentrius RS1xx External RTD Temp Probe (+180°C / +350°F) which is available with Low Temp RTD Probe and High Temp RTD probe

Those version and probes aren't interchangeable.

For instance, If you take an RS1xx External Temp Sensor, it won’t be equipped with humidity sensor.
In a same way, you won’t be able to use an RTD probe on an Ext Temp Sensor.

It's also good mentioning that all of External Temp and RTD Sensors will work correctly if and only if their temperature probes are connected and well tighten. You can refer to this guide for installation : User Guide - Sentrius RS1xx Ext. Temperature Sensors

Also, ensure that your RS1xx is loaded with the last firmware version. This can be uploaded using the Sentrius mobile application.

Last but not least, please make sure to check your RS1xx part number to confirm this is the version you think it is.

If non of the above work, please contact Laird Connectivity Support.

When should I replace the Rs186/RS191 batteries?

RS186/RS191 battery discharge is roughly linear up until 20%, at which point the batteries will start to discharge faster. It is recomended to replace the batteries ASAP after reaching 20% depending on the sensors duty cycle.

If your application provides battery notifications/flags then when the capacity reaches 20% would be a good time to push that notification.

While there is a direct correlation between the sensor reported battery capacity and battery voltage, the discharge curve is not completely linear.

Between 100% and 20% its essentially linear but below 20% the battery discharges faster.

Therefore a when the battery reports 50% capacity  it has more like 45% of its run time remaining.

With the 1-Wire Digital Thermometer Probe, a connection problem at power up is indicated by both LEDs on the front panel being
constantly on. This is a visual indicator to the user that there is a communication issue between the sensor and the probe.

Please check the connector/plug of the external temperature probe for proper connection as well as its cable for mechanical damage.

The RS186 has a SiLabs SI7021 sensor  integrated which comes with the following certificate of calibration;
https://www.silabs.com/documents/public/miscellaneous/si70xx-calibration-certificate.pdf

Laird Connectivity does not provide any additional calibration certification.

The Sentrius app, freely available on Android/iOS allows you to play with different scenarios in its battery life calculator/estimator without needing access to the hardware. Note that the range from the gateway in LoRaWAN impacts the datarate/spreading factor which in turn impacts the time on air for each packet which in turn impacts battery life. 
 

The latency of the RS1xx Sentrius LoRa sensor with external magnet open/close sensor is limited by the following reasons:

1) The RS1xx uses two internal dwell times to detect a door open and close. These can be set in the Sentrius smartphone app to a minimum of 5 seconds (which is also the default setting). So any state change faster than 5 seconds will be suppressed and a change or the open/close sensor state won't be transmitted faster than 5 seconds.

2) Independent of the dwell time the RS186 (EU868 region) faces a minimum LoRa uplink interval due to regulatory 1% duty cycle limitations of the 868MHz frequency band. At the maximum data rate (SF7BW125) the airtime is roughly 60msec, which then adds a dead time of 99x60msec=5.94sec. So from this we get a minimum cycle time of roughly 6 seconds. At the minimum data rate (SF12BW125) the airtime is roughly 1480msec plus a dead time of 99x1480msec=2.4min giving a minimum cycle time of roughly 2.5min.

So the latency of a door open/close state detection plus transmission for the RS186 would be 6 seconds at best case (maximum LoRa data rate SF7BW125) and 2.5min at worst case (minimum LoRa data rate SF12BW125).

The latency of the RS191 is not limited by duty cycle restrictions and hence end up at 5 seconds latency purely due to dwell time.

Yes, as long as they are operating on different networks such that AS923 sensors talk to the AS923 gateway and vice versa for AU915 devices. 

No, an RS1xx AS923 sensor will not work with an AU915 gateway because it cannot receive the downlink packets due to differing bandwidth and frequency plans used and therefore will drop off the network.

While the standard RS1xx (455-0001 for North America) can support down to -40°C and RS1xx external sensor (455-0070 for North America) can support down to -55 °C, typical AA batteries do not perform well at below -25 °C. Industrial grade of AA batteries may support lower temperature but they are significantly more expensive that off the shelf standard AA batteries. 

Laird Connectivity is committed to the long-term supply of all its standard embedded wireless modules and packaged products. Laird Connectivity’s products are specifically designed to meet the needs of the industrial and medical markets, which typically require 7 – 10 years product lifecycle. Although Laird Connectivity can’t guarantee that a component used in our products will not be obsoleted and cannot be reasonably substituted, Laird Connectivity can assure customers we will continue to sell our product when we have customer demand and can obtain the necessary components to build our products.

View our full policy here. 

The state change is based on ‘latency’;

1. The RS1xx uses two internal dwell times to detect a door open and close. These can be set to a minimum of 5 seconds (which is also the default setting). So anything faster than 5 seconds will be suppressed and a change or the door won't be transmitted faster than 5 seconds.
2. Independent of the dwell time the RS186 faces a minimum LoRa uplink interval due to duty cycle limitation. At the maximum data rate (SF7BW125) the airtime is roughly 60msec, which then adds a dead time of 99x60msec=5.94sec. So from this we get a minimum cycle time of roughly 6 seconds, hence smaller dwell times than 5 seconds wouldn't make much sense. At the minimum data rate (SF12BW125) the airtime is roughly 1480msec plus a dead time of 99x1480msec=2.4min giving a minimum cycle time of roughly 2.5min.

So the latency of a door open/closed state detection plus transmission would be 6 seconds in a best case scenario (maximum LoRa data rate SF7BW125).

This applies to the RS186 EU version due to duty cycle limitations.

The RS191 will end up at approximately 5 seconds latency, purely due to dwell time.