SBE 21 SeaCAT Thermosalinograph
Configuration Details

• 21-1a provides 1 bulkhead connector for 4 single-ended A/D channels. Single-ended channels are acceptable for sensors that draw very little current & can share power & signal common with SBE 21 without injecting ground line noise into signal.
• 21-1b provides 1 bulkhead connector for 2 differential A/D channels (can also be used with 2 single-ended A/D sensors). Sensors that draw larger amounts of current generate ground line noise which interferes with signals. For these sensors, when power & signal common are shared, a differential channel is needed. Differential input amplifiers are able to distinguish & reject noise from signal.

Note: 21-1a & -1b do not include auxiliary sensors, mounts, or interface cables.

Many auxiliary sensors are electrically compatible with SBE 21; these sensors can be purchased from Sea-Bird & integrated with SBE 21 at our factory, or you can purchase cables from Sea-Bird & perform integration yourself. Note that integration of these sensors at Sea-Bird is limited to providing appropriate cable & setting up instrument configuration file. Sea-Bird does not provide methods for mechanical integration of these auxiliary sensors with SBE 21. User must design / provide flow-through chamber that receives outflow from SBE 21 for auxiliary sensors.

• See Third Party portion of price list for ordering details on fluorometers, transmissometers, turbidity meters, etc. that are electrically compatible with SBE 21. These sensors can be purchased from Sea-Bird, along with appropriate cables. Alternatively, you can purchase sensors from third party manufacturers, & purchase cables from Sea-Bird.

User can change sensors on SBE 21 in field, if combination is compatible with auxiliary A/D channel configuration selection. However, bulkhead connector requires Y-cable to connect multiple auxiliary sensors to SBE 21; each Y-cable is unique to sensors being integrated, so changing sensors may require changing Y-cable.

Standard SBE 21 with serial number greater than 3110 supports input from remote SBE 38 thermometer through 4-pin remote temperature connector, providing sea surface temperature. Ideal location for SBE 38 is on pipe near seawater intake, as close to ship's bow as possible, to minimize water temperature changes due to ship's thermal mass. User can add SBE 38 to system at any time.

• Some custom SBE 21s with serial number less than 3345 & greater than 3110, & all standard SBE 21s with serial number less than 3110, supported input from remote SBE 3 temperature sensor through a 3-pin remote temperature connector. Current SBE 21 electronics does not support SBE 3 as remote temperature sensor.

• PN 17015 -- AC power cable
• PN 80438 (DN 31063) -- 10 m cable for connection to SBE 21
• PN 17031 (DN 30581) -- 2.4 m pigtail cable for connection to SBE 21
• PN 801424 (DN 32787) -- 1.8 m NMEA test cable for connection to computer simulating NMEA input for testing NMEA interface. NMEA simulation program, NMEATest, is part of Seasoft software, & is installed when you install SBE Data Processing.
• PN 171887 (DN 32431) -- 3 m cable for connection to computer
• PN 171888 -- Cable adapter, DB-25S to DB-9P (for use with computer with DB-25 connector)
• PN 50368 -- connector assembly for 4-pin SeaCAT Data I/O (for connection to SBE 21)
• PN 50369 -- connector assembly for 5-pin NMEA Input (for connection to NMEA device -- can acquire latitude/longitude & depth data)

Note: Order 50107 instead of 50298 for use with SBE 21 that has 3-pin bulkhead connector for remote temperature input -- compatible with SBE 3 Temperature Sensor. All standard SBE 21s with serial number less than 3110 & some custom SBE 21s with serial number less than 3345 & greater than 3110 are compatible with SBE 3 Temperature Sensor. See document 67060 for complete listing of parts.

50315 -- slide Tygon on end of conductivity cell

• SBE 21s shipped before 2002 used a smaller anti-foulant device inside Tygon tubing that attached to end of conductivity cell, & did not include 50315. For those SBE 21s, order 50315 & 801542 AF24173 Anti-Foulant Devices first time you need new Anti-Foulant Devices. Once you have 50315, order AF24173 Anti-Foulant Devices as needed.
• SBE 21s shipped after 2002 include 50315 & 801542 installed on SBE 21. Order AF24173 Anti-Foulant Devices as needed.

Fits inside water jacket. 90399.1 is for use with SBE 21 that is compatible with SBE 38 Temperature Sensor (standard SBE 21 with serial number > 3110 -- supports input from remote SBE 38 thermometer through 4-pin remote temperature connector).

Note: Order PN 90387.1 instead for use with older SBE 21 that is compatible with SBE 3 Temperature Sensor -- supports input from remote SBE 3 thermometer through 3-pin remote temperature connector.