Overview

This document will help you:

  1. Troubleshoot your lab monitoring installation (self-managed or managed installation)
  2. Understand what to expect from your sensors
  3. Diagnose wifi coverage or connectivity issues

Subscriptions: Any
Technical prerequisites: Physical access to links, access to TetraScience Dashboard.

Background

Often the first steps we take to troubleshoot sensor or wifi issues are fairly simple, so we have published a selection of the more common procedures here.

Power

The first generation TetraScience Link is powered with a provided Micro USB cable. If your link is offline, the first thing to check is that this cable is plugged in and receiving power. To tell if your link is receiving power, you can check the LED indicators on the side.

For a first generation device, you are looking for a solid red light, either alone or with a blinking green light. Solid red and solid green means that the device has not started properly, unplug the micro-USB cable and try again.

The second generation device has a round 'barrel jack' type power connector. This is not interchangeable with the first generation, although power requirements are similar.

For a second generation device, you are looking for a green light on the side, as shown.

Dracal RTD Sensor

It is usually fairly easy to tell if there is something wrong with a temperature sensor. Physical damage or disconnections will often result in 'impossible' readings' or no reading, so if your freezer suddenly starts reporting that it is 1000C, your sensor is probably damaged or disconnected. Below are some things you can check.

Loose USB connection: unplug and plug the USB RTD sensor and then reboot the Link.

RTD to USB adapter connection: there are 3 wires that connect the probe to the USB adapter. If any of these wires comes loose, it could cause incorrect readings. Below (circled) is how the connection should look.

Pull gently on these three wires- they should not come out of the green terminal block. If they do, you'll see the end of the wire(s) poking out like this:

This can be reattached with a small flathead screwdriver (like an eyeglass screwdriver).

Dracal TRH Sensor

Dracal temperature and humidity sensors, while rated for very high humidity, are not waterproof, and will occasionally have problems due to condensation buildup. If condensation builds up, the sensor reading start to 'saturate', basically, always reading 100% humidity. To fix this try the following:

  1. Remove the TRH sensor from the humid environment and leave it out to dry for a few days.
  2. Reinstall the sensor, making sure that the tip of the sensor is pointing downward so that any condensation drips off instead of pooling on the sensor (see image below). 

WiFi Connectivity

Sometimes, depending on a variety of factors, one or more of your links may lose connection to the internet. Factors may include: amount of traffic on the network, wifi signal strength, noise from other devices, internet outages, power outages/issues, etc.

Before you attempt any WiFi troubleshooting, check first that the internet is working (via your computer) and that your Link is powered on. (Links have a small LED indicator light that should be on all the time)

Also, disconnections are usually temporary and links should automatically reconnect on their own. Proceed with troubleshooting if a) your Link has been offline for >40min. or b) you have frequent disconnection events.

  1. Power Cycle the Link: remove power cord, wait 10 seconds, and plug it back in. Check that the link indicator light comes on.
  2. Try connecting to the WiFi with your phone to see if WiFi coverage exists where the link is installed. WiFi coverage from a single router is often not uniform. If you are in a room or area of a room where WiFi coverage is poor, this will affect your link. Some places this might be an issue are underneath desks, behind large, metal instruments, or simply a few rooms away from the access point.
  3. If you consistently have poor wifi performance, you may want to refer to our networking prerequisites document to see if you might need to make changes to your WiFi infrastructure: http://docs.tetrascience.com/hardware-installation/background/networking-prerequisites 
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