Seabird CTD-Carousel Setup & Deck Unit Diagnostics

SIO-CalCOFI’s method of terminating the sea cable uses a custom 4-pin pigtail to terminate a multi-strand conductive wire that allows each individual conductor to be used in any combination. Terminating the sea cable using this technique may be viewed in the CalCOFI Handbook: CTD Termination.

Conventional two-pin Seabird pigtail terminations are standard on NOAA vessels and are usually performed by the ET. So interfacing the CTD deck unit only requires the attachment of the sea cable to the deck unit. This is done by connecting a two-conductor wire, such as Seabird part no. 31371 or a coaxial cable equipped with MS3106A connector, from the winch junction box in the CTD lab to the Sea Cable port on the back of the deck unit (see the deck unit section below).
Once the sea cable is connected to the Seabird 9plus and Seabird 11plus deck unit, the deck unit can be powered on. If cabled properly and all electronics are functioning, the numeric LED panel of the deck unit should display non-zero numbers. These values are different for each channel which can be selected by rotating the WORD SELECT dial to the right of the LED panel.
If the LED panel displays “0.0.0.0.0.0.0.0” then the deck unit and CTD “fish” are not handshaking correctly. Turn the deck unit off and wait 60 seconds before touching any exposed wire. Typically, with only two pins, the problem is reversed polarity so switching the wires in the junction box will correct this issue. Please note that powering on the deck unit with reversed polarity may blow the fuse(s). So after switching the wires and before re-powering on the deck unit, check both the 1/2A and 2A fuses on the back of the deck unit & replace if necessary. It is prudent to keep a good supply of these fuses on hand. Power on the deck unit and hopefully, the LED panel has numbers.

Please note in the photos, yellow tape is used to keep the deck unit Signal Source set to Fish. If the switch is toggled to Tape, the deck unit will not communicate with the CTD. The yellow tape prevents the switch from changing from Fish to Tape unintentionally.