Troubleshooting Temperature Sensor Issues

Troubleshooting: Safe Food Pro Hardware Not Sending Readings

Is your Safe Food Pro hardware (Sensors and Hubs) no longer sending temperature or other readings to your online dashboard? This guide will help you identify the potential cause and resolve the issue, often without needing to contact support.

Goal:

  • Narrow down the source of the problem (Hub, Network, Power, or Sensor).
  • Follow steps to fix the connection.

Quick Checks Before You Start


Before diving into detailed troubleshooting, try these common fixes:


  1. Check the Dashboard: Log in to your Safe Food Pro web dashboard.
    • Look at the Temperature Sensing graph or Sensor list.
    • Are all sensors offline, or just one?
    • For the affected sensor(s), check the Last Reading Time. Has it been a long time?
    • Check the reported Battery Voltage (should be above ~3.5V).
    • Check the Signal Strength (RSSI). Ideally, this should be better (less negative) than -100dBm (e.g., -60dBm, -80dBm are good). Values closer to -120dBm indicate a very weak signal prone to dropouts.
  2. Power Cycle the Hub: If ALL sensors stopped reporting around the same time, the issue is likely the Hub.
    • Unplug the Hub from the power outlet.
    • Wait 30 seconds.
    • Plug the Hub back in.
    • Wait a few minutes for it to reconnect (watch the lights - see below). Readings should reappear on the dashboard within the next hour (sensors typically report every 15 mins).
  3. Power Cycle the Sensor: If only ONE sensor is offline, try restarting it.
    • Carefully unscrew the sensor's casing.
    • Remove the battery.
    • Wait 30 seconds.
    • Reinsert the battery correctly.
    • Screw the casing back on securely.
    • Place the sensor near the Hub if possible and check the dashboard over the next hour to see if it reports.

Troubleshooting Hub Issues

Your Hub acts as the gateway between your Sensors and the Safe Food Pro dashboard. If all your sensor readings stop transmitting simultaneously, or if you've never received readings, the Hub is the most likely area to investigate.

Step 1: Check the Hub Lights


The indicator lights on your Hub provide crucial information. Observe the lights:


A Healthy Hub Shows:

  • Power Light:
    • Colour: Red
    • Behaviour: Solid (continuously on)
  • Network Light:
    • Colour: Green
    • Behaviour:
      • Quick Flashing (Sending data)
      • Two Seconds ON - Successfully sent data
      • Once all data is sent it'll be in an idle state. (0.1 sec on, 5 seconds off)
  • RF Light (Radio Frequency):
    • Colour: Blue
    • Behaviour: Flashes briefly each time a reading is received from any Sensor (usually every 15 mins, but could be more frequent if many sensors are present). Clicking the button on a sensor can trigger a test transmission.

If any light is behaving differently, proceed to the relevant section below.





Decoding the (green) Net Light Status



LAN Hub

The "Net light" provides visual cues about the operation and status of the device, particularly when it's interacting with Wi-Fi.

  • Solid Green Light (Keep on always): The module is in OTA (Over-the-Air) mode or is in configuration mode for reading or writing to its Wi-Fi module settings.
  • Blinking Rapidly (On 0.1 second, off 0.1 second): The module is currently sending data.
  • Solid Green Light for 2 Seconds (Keep on 2 seconds): This indicates that data has been sent successfully.
  • Off for 2 Seconds (Off 2 seconds): This signifies that data sending has failed.
  • Quick Flash, then Long Pause (On 0.1 second, off 5 seconds): The module is idle or "free," meaning it's not actively performing any tasks.
  • Blinking Slowly (On 2 seconds, off 2 seconds): The module is undergoing initialization.

4G Hub

This light indicates the status related to the gateway's network connectivity (e.g., GPRS, 4G, or other network configurations).

  • Solid Green (On without flashing): The gateway is in OTA / configuration read or write mode, or it is connected to a network.
  • Rapid Blink (On for 0.1 second then off for 0.1 second): The gateway is unable to read the IMEI (International Mobile Equipment Identity) or is waiting for a phone to be connected (perhaps for initial setup or tethering).
  • Short Flash, Longer Off (On for 0.1 second then off for 0.2 second): The gateway is receiving an SMS.
  • Short Flash, Long Off (On for 0.1 second then off for 0.9 second): The gateway is connected to the GPRS network.
  • Short Flash, Very Long Off (On 0.1 for second then off for 2.9 seconds): The gateway is connected to the 4G network.
  • Long Flash, Longer Off (On for 1 second then off for 2 seconds): The gateway is unable to connect to the 4G network.
  • Even Blinking (On for 0.5 second then off for 0.5 second): The gateway is unable to read the SIM card.

Troubleshooting Network Issues


Network problems are typically indicated by the Green Network Light on the Hub.


Troubleshooting Network Connectivity:


For LAN Hubs (Model WH-2 - connected via Ethernet cable):


  • Check Physical Connections: Ensure the Ethernet cable is securely plugged into the LAN port on the Hub and into your router or network switch. Try a different port on your router/switch. Ensure the cable isn't damaged.
  • Check Network Equipment: Ensure your router and any network switches are powered on and have internet access. Try restarting your main internet router.
  • Firewalls & Security: Corporate or complex networks often have firewalls. Safe Food Pro Hubs need outbound access to admin.lora.safefoodpro.co.nz via TCP port 3000.
    • Action: Contact your IT department or network administrator to confirm this port is open and the address isn't blocked.

For 4G Hubs (Connected via Cellular SIM card):


  • Check SIM Card:
    • Ensure the SIM card is active and has data credit with the provider (e.g., Spark, unless using your own).
    • Confirm the SIM card is installed correctly in the Hub. Power cycle the hub after checking/re-inserting the SIM.
  • Check Cellular Signal: Ensure the Hub is placed in an area with adequate mobile reception for the SIM provider. Metal enclosures or basement locations can block signal. Check the 4G antenna is screwed on correctly.

If network troubleshooting doesn't resolve the issue, please contact support@safefoodpro.com.

Troubleshooting Power Issues


Power supply problems are usually indicated by the Red Power Light or the Hub failing to power on.


Symptoms of a Power Issue:

  • The Hub does not turn on at all (no lights).
  • The Red Power Light flashes continuously instead of being solid red.

Troubleshooting Power Supply:

  • Check Connections: Ensure the power adaptor cable is securely plugged into the Hub and the power adaptor block is firmly plugged into the wall socket.
  • Try Another Outlet: Plug the power adaptor into a different known-working wall outlet.
  • Check the Adaptor Light: Most Safe Food Pro power adaptors have a small blue indicator light on the adaptor block itself:
    • Blue light is FLASHING: Indicates an issue with the power adaptor itself.
    • Blue light is SOLID: Indicates the adaptor is likely providing power, and the issue may be within the Hub unit.

If you suspect a faulty power adaptor or Hub, please contact support@safefoodpro.com.

Troubleshooting a Single Offline Sensor

If only one specific sensor has stopped sending readings, the problem is likely with that sensor or its direct environment/connection to the hub.


Start Here: Check the dashboard for the sensor's Last Reading Time, Battery Voltage (needs >3.5V), and Signal Strength (RSSI, needs >-100dBm ideally).


1. Check/Replace Sensor Battery


Low batteries are the most common cause for a single sensor failing.

  • Check Voltage: View the sensor's details on the web dashboard. If the voltage is near or below 3.5V, the battery needs replacing soon.
  • Battery Life: Batteries typically last around 3 years, but this varies greatly depending on temperature (extreme cold shortens life significantly) and how often it transmits.
  • Battery Type: Safe Food Pro sensors use a specific 3.6V Lithium battery (often type EVE ER18505 or similar). Using standard AA alkaline batteries will not work correctly.
  • Replacement:
    1. Carefully unscrew the sensor's casing.
    2. Note the orientation (+/-) of the old battery.
    3. Remove the old battery.
    4. Insert the new, correct 3.6V Lithium battery.
    5. Securely screw the casing back together, ensuring any seals are seated correctly.
    • Replacement batteries can be ordered from the Safe Food Pro online shop (NZ or AU) or potentially specialized battery suppliers.
  • After Replacement: The sensor should connect and report within its next cycle (usually 15 mins). Check the dashboard for updated battery voltage and readings.

2. Check Sensor Range & Signal Strength (RSSI)

If the battery is good, the sensor might be too far from the hub or something is blocking the signal.

  • Signal Strength (RSSI): Check this on the dashboard.
    • Good: > -100dBm (e.g., -60, -75, -90dBm)
    • Weak/Marginal: -100dBm to -120dBm (prone to dropping out)
    • Very Poor/No Connection: < -120dBm or no reading
  • Obstructions: The signal (which uses LoRaWAN technology) can be blocked or weakened by:
    • Metal: Fridge/freezer walls, stainless steel shelving, large metal containers.
    • Concrete: Thick walls or floors.
    • Water/Ice: Dense liquid storage, significant ice build-up.
    • Dense Product: Fully packed cool rooms or freezers.
    • Distance: While the theoretical range is long, practical indoor range is significantly reduced by obstructions.
    • People: Can temporarily obstruct signals.
  • Troubleshooting Steps:
    1. Test Connection: Temporarily move the affected sensor right next to the Hub. Wait up to an hour. Does it appear on the dashboard with a strong signal?
      • If YES: The original location has a range or obstruction issue. See step 2/3.
      • If NO (and battery is good): The sensor itself might be faulty (Contact Support).
    2. Improve Placement: If range/obstruction is the issue:
      • Move the sensor inside the fridge/freezer closer to the door, higher up, or away from metal walls/corners.
      • Ensure the antenna on the sensor is screwed on properly and oriented vertically if possible.
    3. Move the Hub: Consider moving the Hub closer to the problematic sensor location. This might require a longer Ethernet cable (for LAN hubs). Ensure the Hub itself is placed in an open area, not inside a metal cabinet.

3. Check for Interference

  • Wireless signals can be affected by strong electromagnetic interference.
  • Ensure the sensor (and Hub) are not placed directly beside potential sources like microwaves, large electric motors, or other high-power radio equipment.

4. Check for Physical Damage or Environmental Issues

  • Inspect the Sensor: Look for cracks in the casing, signs of water getting inside, or damage to the antenna.
  • Temperature: Ensure the sensor is operating within its rated temperature range (-40°C to +125°C). However, remember battery performance degrades significantly in extreme cold (below freezing) or heat (above ~50°C).
  • Condensation: If moving sensors between very different temperatures (e.g., freezer to room temp), allow time for condensation to dissipate before assuming a fault.

5. Check Sensor Association

  • Less common, but ensure the sensor's unique ID is still correctly assigned to its designated location/equipment in the Safe Food Pro Administration Console settings (under Equipment or Sensors).

Still Having Trouble? Contact Support

If you've worked through these steps and your hardware is still not transmitting readings reliably, please reach out to our support team.

  • Email: support@safefoodpro.com
  • Include Details: To help us diagnose the issue faster, please provide:
    • Your Business Name.
    • Which hardware is affected (Hub model WH-2/4G, or specific Sensor ID/Name).
    • If Hub issue: Status of the Hub lights (Power, Network, RF).
    • If Sensor issue: Sensor ID, Last Reading time, reported Battery Voltage, and Signal Strength (RSSI) from the dashboard (if available).
    • Description of the sensor's location (e.g., "Walk-in freezer, back wall", mention nearby metal shelving).
    • Approximate time the issue started.
    • The troubleshooting steps you have already tried from this guide.

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