Blog Home » Paperclips – Valuable Troubleshooting Tools?

Blog Home » Paperclips – Valuable Troubleshooting Tools?

Paperclips – Valuable Troubleshooting Tools?

Troubleshoot comms with the quick and easy Loop Back Test

January 2020 Newsletter

Paperclips are handy, but have you used one to troubleshoot an oceanographic sensor? When you’re unable to communicate with your instrument, the humble paperclip is one of the first tools that Sea-Bird Scientific’s technical support team reaches for. Learn how to troubleshoot comms with the quick and easy Loop Back Test.

Learn More

RS 232 Closeup

The Loop Back Test

Most Sea-Bird Scientific instruments utilize RS-232 telemetry. This tried-and-tested communication method is common among scientific instruments, and allows users to interact with their equipment via simple terminal software. However, when an instrument is not communicating, the root cause is likely one of four common reasons:

  1. The cable connecting the instrument to the computer is broken.
  2. The incorrect serial port is selected in the terminal software.
  3. The baud rate setting in the terminal software does not match the instrument baud rate.
  4. Instrument Problems – no power, incorrect configuration, etc.

The Loop Back Test can quickly eliminate the first 2 possibilities, allowing you to focus on troubleshooting the instrument itself if necessary. Gather a paperclip, your RS-232 cable, and a USB-serial adapter if necessary. From there, the process is simple:

  1. Start up the terminal software.
  2. Connect the communication cable to the computer’s serial port or USB-serial adapter.
  3. Using the paperclip, bridge pins 2 and 3 on the cable’s instrument-end (see picture above).
  4. Type “abcd” into the terminal.
    1. If “abcd” appears in the terminal, the cable is working and the correct serial port is selected in the terminal program. Reconnect the cable to the instrument and try communicating at different baud rates.
    2. If these characters do not appear in the terminal, verify that the correct serial port is selected in the terminal and repeat the test. Try a new cable if necessary.

The Loop Back Test bridges the RS-232 Transmit (TX) and Receive (RX) lines. Typing into the terminal sends these characters out the TX line, through the paperclip, into the RX line, and back into the terminal.

January 1, 2020

Related Posts

Featured Posts

Pride 2023

Celebrating and honoring our LGBTQIA+ communities At Sea-Bird Scientific, we are proud to stand with members of the LGBTQIA+ community during Pride Month 2023. As with last year, we changed our logo on social media to feature a rainbow throughout the month of June in...

What is the UN Ocean Decade?

Did you get a chance to read about the HyperNAV program that we support in partnership with NASA? Sea-Bird Scientific is proud to be part of the NASA PACE Mission, which contributes to the UN Ocean Decade's 7 Outcomes. On December 5, 2017, the United Nations declared...

World Oceans Week at Sea-Bird Scientific: The HyperNAV Program

A New Paradigm for Ocean Color Satellite Calibration The HyperNAV program is part of the NASA PACE (Plankton, Aerosol, Cloud, Ocean Ecosystem) Mission, set to launch in 2024. The NASA PACE Mission is an initiative aimed at helping scientists understand how carbon...

Contact Us



show more
Secured By miniOrange