Dragino S31-CB/S31B-CB NB-IoT/LTE-M Outdoor Temperature and Humidity Sensor

1. Introduction

The Dragino S31-CB and S31B-CB are advanced NB-IoT/LTE-M Temperature and Humidity Sensors designed for Internet of Things (IoT) solutions. These devices precisely measure ambient temperature and relative air humidity, then transmit this data to an IoT server via NB-IoT or CAT-M1 networks.

The sensor utilized in both S31-CB and S31B-CB models is the SHT31, a fully calibrated, linearized, and temperature-compensated digital output sensor from Sensirion. It offers strong reliability and long-term stability. The SHT31 is housed within a waterproof, anti-condensation casing, ensuring durability for extended use.

The S31-CB/S31B-CB supports various uplink methods including MQTT, MQTTs, TCP, UDP, or CoAP, catering to diverse application requirements and enabling connectivity with a wide range of IoT servers.

Powered by an 8500mAh Li-SOCI2 battery, these sensors are engineered for long-term operation, potentially lasting several years. Actual battery life may vary based on environmental conditions, data update frequency, and chosen uplink method. Optional built-in SIM cards and default IoT server connection versions are available for simplified configuration.

2. Key Features

• Network Bands:
  • For -NB Bands: B1/B2/B3/B4/B5/B8/B12/B13/B17/B18/B19/B20/B25/B28/B66/B70/B85
  • For -CB Bands: B1/B2/B3/B4/B5/B8/B12/B13/B18/B19/B20/B25/B28/B66/B71/B85
• CAT-M1 / LTE-M Bands: B1/B2/B3/B4/B5/B8/B12/B13/B18/B19/B20/B25/B26/B27/B28/B66/B85
• Ultra Low Power Consumption
• Monitors environment temperature and relative air humidity
• Temperature & Humidity alarm functionality
• Supports multiple sampling and single uplink
• 8500mAh Li-SOCI2 battery for extended use
• 3-meter sensor cable (for S31-CB model)
• Supports BLE remote configuration and firmware updates
• Periodic data uplink
• IP66 Waterproof Enclosure
• Configurable parameters via AT Commands
• Uplink via MQTT, MQTTs, TCP, UDP or CoAP

3. Applications

The Dragino S31-CB/S31B-CB sensor is suitable for a wide range of IoT applications requiring environmental monitoring:

• Smart Buildings & Home Automation
• Logistics and Supply Chain Management
• Smart Agriculture
• Smart Cities

4. Specifications

4.1. General Characteristics

• Supply Voltage: 2.6V ~ 3.6V
• Operating Temperature: -40°C ~ 85°C

4.2. Temperature Sensor (SHT31)

• Range: -40°C to +80°C
• Accuracy: ±0.2°C @ 0-90°C
• Resolution: 0.01°C
• Long Term Shift: <0.03°C/yr

4.3. Humidity Sensor (SHT31)

• Range: 0 ~ 99.9% RH
• Accuracy: ±2% RH (0 ~ 100% RH)
• Resolution: 0.01% RH
• Long Term Shift: <0.25% RH/yr

4.4. NB-IoT Module (BC660K-GL)

• Support Bands:
  • B1 @H-FDD: 2100MHz
  • B2 @H-FDD: 1900MHz
  • B3 @H-FDD: 1800MHz
  • B4 @H-FDD: 2100MHz
  • B5 @H-FDD: 860MHz
  • B8 @H-FDD: 900MHz
  • B12 @H-FDD: 720MHz
  • B13 @H-FDD: 740MHz
  • B17 @H-FDD: 730MHz
  • B18 @H-FDD: 870MHz
  • B19 @H-FDD: 870MHz
  • B20 @H-FDD: 790MHz
  • B25 @H-FDD: 1900MHz
  • B28 @H-FDD: 750MHz
  • B66 @H-FDD: 2000MHz
  • B70 @H-FDD: 2000MHz
  • B85 @H-FDD: 700MHz

4.5. Battery

• Type: Li/SOCI2 un-chargeable battery
• Capacity: 8500mAh
• Self-Discharge: <1% / Year @ 25°C
• Max Continuous Current: 130mA
• Max Boost Current: 2A, 1 second

4.6. Power Consumption

• STOP Mode: 14uA @ 3.3V
• Max Transmit Power: 350mA @ 3.3V

4.7. Model Variants and Options

The S31/S31B series offers various models with different connectivity and features:

5. Setup Guide

5.1. Unboxing and Initial Inspection

Upon receiving your Dragino S31-CB/S31B-CB sensor, carefully unbox all components. Verify that the package contains the sensor unit, antenna, and any ordered accessories (e.g., external SHT31 sensor for S31-CB). Inspect for any visible damage.

5.2. Antenna Installation

Locate the antenna connector on the sensor unit. Carefully screw the provided antenna onto the connector until it is finger-tight. Do not overtighten.

5.3. External Sensor Connection (S31-CB only)

If you have the S31-CB model with an external SHT31 sensor, connect the sensor cable to the designated port on the main unit. Ensure a secure connection to maintain the IP66 waterproof rating.

5.4. Powering On and Initial Configuration

The sensor is powered by an internal 8500mAh Li-SOCI2 battery. It is typically shipped with the battery already installed. To activate the device or perform initial configuration:

1. The device may have a power button or a magnetic switch for activation. Refer to the specific model's quick start guide for exact power-on procedures.
2. For initial configuration, you can use AT Commands via a serial interface or utilize the BLE (Bluetooth Low Energy) remote configuration feature. This allows you to set parameters such as uplink intervals, network credentials, and IoT server details.
3. If your device includes a pre-configured SIM card and IoT server connection, minimal configuration may be required.

6. Operation

6.1. Data Collection

Once configured and powered on, the S31-CB/S31B-CB sensor will begin collecting temperature and humidity data from its SHT31 sensor at predefined intervals.

6.2. Data Uplink

The collected data is transmitted to your chosen IoT server using the configured NB-IoT or CAT-M1 network. The device supports various uplink protocols including MQTT, MQTTs, TCP, UDP, or CoAP. Data uplink occurs periodically as per your settings.

6.3. Temperature & Humidity Alarms

The sensor can be configured to trigger alarms based on predefined temperature and humidity thresholds. When an alarm condition is met, the device can send an alert to the IoT server, enabling timely responses to critical environmental changes.

7. Maintenance

7.1. Battery Life

The 8500mAh Li-SOCI2 battery is designed for long-term use. However, its lifespan is influenced by factors such as uplink frequency, environmental conditions (especially extreme temperatures), and network signal strength. Monitor battery levels via your IoT platform if available. The battery is un-chargeable and will need replacement at the end of its life.

7.2. Enclosure Care

The sensor features an IP66 waterproof enclosure, providing protection against dust and powerful water jets. Regularly inspect the enclosure for any signs of damage or cracks that could compromise its waterproof integrity. Keep the sensor clean from excessive dirt or debris that might obstruct the sensor opening (for S31B-CB) or the external probe (for S31-CB).

7.3. Firmware Updates

Periodically check the manufacturer's website for available firmware updates. Firmware updates can improve performance, add new features, or address bugs. Updates can typically be performed remotely via BLE.

8. Troubleshooting

8.1. No Data Uplink

• Check Network Coverage: Ensure the sensor is within range of a stable NB-IoT or CAT-M1 network. Refer to Figure 7 for general coverage information.
• Verify SIM Card: If using a SIM card, ensure it is correctly inserted, activated, and has an active data plan.
• Configuration: Double-check network credentials (APN, etc.) and IoT server settings (address, port, authentication) using AT commands or BLE configuration tool.
• Antenna: Ensure the antenna is securely attached.
• Battery: Check if the battery is depleted.

8.2. Incorrect Temperature/Humidity Readings

• Sensor Obstruction: Ensure the sensor opening (S31B-CB) or the external probe (S31-CB) is not blocked by dirt, debris, or condensation.
• Environmental Factors: Avoid placing the sensor in direct sunlight, near heat sources, or in areas with poor air circulation, which can affect readings.
• Sensor Damage: If readings are consistently erratic or outside expected ranges, the SHT31 sensor might be damaged.

8.3. Short Battery Life

• Uplink Frequency: Reduce the data uplink interval if possible. More frequent uplinks consume more power.
• Network Signal: Poor network signal strength forces the module to use more power to transmit, reducing battery life. Relocate the sensor to an area with better signal.
• Extreme Temperatures: Operating in very cold or very hot environments can reduce battery efficiency.

9. User Tips

No specific user tips are available from customer reviews or Q&A at this time. However, general best practices for IoT sensors include:

• Optimal Placement: For accurate readings, place the sensor in a location representative of the environment you wish to monitor, away from direct heat sources, cold drafts, or direct sunlight.
• Network Planning: Before deployment, verify NB-IoT or LTE-M network coverage in your intended installation area to ensure reliable data transmission.
• Regular Monitoring: Utilize your IoT platform's dashboard to regularly monitor sensor data and battery status to ensure continuous operation.

10. Warranty and Support

For warranty information, technical support, or service inquiries, please contact the seller or the manufacturer directly. Keep your purchase receipt or order details handy when contacting support.