SOP: Investigating Cable and Connector Issues

Owned by Gøran Pedersen Krangsås
Last updated: Nov 29, 2024
3 min read

Purpose
This guide helps determine if a cable or connector is causing an unstable connection to a sensor. Symptoms of a poor connection include gaps in echograms seen in Inspector and Grafana due to unstable communication between the CPU and the sensor.

Possible Causes

Unstable connections may result from one of the following:

  1. Cage Cabinet

    1. Inner Cabinet

      1. Internal Cables (from sensor port to CPU)

      2. CPU

  2. Cable

    1. Connector

  3. Sensor

Step 1: Photos and LED-activity in CPU

Some photos before- and after enables us to better understand the root cause and gives us a better oppurtunity to implement a solution.

image-20241129-092321.png

Its of great interest to know the LED activity on the port before- and after. LED activity indicates active communication to the sensor.

image-20241129-091938.png

Step 2: Test the Inner Cabinet (Port Replacement)

If only one sensor is experiencing issues, the problem could be with the port connection in the Inner Cabinet. By swapping ports, we can see if the problem follows the sensor or stays with the port.

Example:

  • Scenario: The top sensor has a poor connection.

  • Current Setup:

    • Top sensor → Port A

    • Bottom sensor → Port B

Swap the Connections:

  • Connect the top sensor to Port B.

  • Connect the bottom sensor to Port A.

Possible Outcomes:

  1. Outcome 1: Top sensor works in Port B, and the bottom sensor stops working in Port A.

    • Diagnosis: Port A in the Cage Cabinet is likely faulty.

    • Solution: Replace the Cage Cabinet.

  2. Outcome 2: Both sensors work after the swap.

    • Diagnosis: The Cage Cabinet is working fine. The issue might be with the cable or sensor.

  3. Outcome 3: The top sensor still does not work, but the bottom sensor works.

    • Diagnosis: The Inner Cabinet is functional. The problem is likely with the cable or top sensor.

Step 3: Determine if the Issue is with the Cable or Sensor

Now that we've ruled out the Cage Cabinet, let's check if the cable or sensor is causing the issue.

Inspect the Connector

The connector has three main parts:

  1. Contacts – The end of the connector where the conductive components are located.

  2. Housing – The outer shell that holds the connector together.

  3. Strain Relief – Prevents stress on the wires and is closest to the cable.

Inspection Steps:

  1. Check for Rotation:

    • The parts should not rotate against each other easily. If they do, inspect for:

      • Humidity, Water, or Corrosion: Look inside and outside the connector for signs of moisture or corrosion.

    • If rotation is present, reassemble the connector firmly.

  2. Check for Firmness:

    • Ensure there is no rotation or looseness.

    • Inspect the outside for corrosion or any visible damage.

  3. Reconnect and Test:

    • Once the connector is firmly reattached, plug it back into the Inner Cabinet port.

    • Check the LED activity to confirm if the sensor is now operational.

Note: If the sensor remains unresponsive after these checks, the issue may lie with the sensor itself. We will then need to replace the sensor.