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SBE 37 MicroCAT Feature Comparisons

Publication Date: 
Wednesday, July 29, 2015
MicrocatFeatureComparisonsJuly15.pdf546.48 KB

Sea-Bird manufactures a number of instruments within our MicroCAT CTD family, which make measurements at user-programmable intervals. All MicroCATs:

  • Measure Conductivity and Temperature.
  • Can include an optional strain-gauge Pressure sensor.
  • Can include an integrated pump (P in the model number designation) for improved bio-fouling protection and improved conductivity and oxygen sensor response.
  • Have 8 Megabyte memory.
  • Are available for depths to 350 meters (plastic housing) or 7000 meters (titanium housing).

Some MicroCATs also include Dissolved Oxygen:

  • IDO MicroCATs include a membrane-type Dissolved Oxygen sensor.
  • ODO MicroCATs include an Optical Dissolved Oxygen sensor.

The SBE 37-SMP-ODO MicroCAT can be integrated with a pH sensor to provide CTD + DO + pH:

  • SeapHOxTM (37-SMP-ODO with SeaFETTM pH Sensor) is rated to 50 m depth.
  • Deep SeapHOxTM (37-SMP-ODO with Deep SeaFETTM pH Sensor) is rated to 2000 m depth.

Other features vary:

Model Number
Included Sensors
Pump* Power Communication Real-Time
Sampling Interval
Internal External
37-SMP-ODO Optical Dissolved Oxygen
(plus pH when integrated
with SeaFETTM or Deep SeaFETTM)
RS-232, RS-485, or SDI-12 10 sec

(replaced by
Dissolved Oxygen
(membrane type)
RS-232 or RS-485 10 sec
37-SMP   RS-232, RS-485, or SDI-12 6 sec
37-SM     RS-232 or RS-485 6 sec
37-SIP-IDO Dissolved Oxygen
(membrane type)
  RS-232 or RS-485 1.0 sec
37-SIP     RS-232 or RS-485 1.0 - 1.5 sec ***
37-SI       RS-232 or RS-485 1.0 - 1.5 sec ***
37-IMP-ODO Optical Dissolved Oxygen   Inductive Modem **** ** 10 sec

(replaced by
Dissolved Oxygen
(membrane type)
  Inductive Modem **** ** 10 sec
37-IMP     Inductive Modem **** ** 6 sec
37-IM       Inductive Modem **** ** 6 sec

* Integral pump provides improved conductivity and dissolved oxygen (if applicable) response, and conductivity fouling protection.
** Inductive Modem MicroCATs do not automatically transmit real-time data; controller must query for data.
*** Minimum sampling interval 1.0 sec without optional pressure sensor, 1.5 sec with optional pressure sensor.
**** See Application Note 92 for a description of Inductive Modem telemetry.

Applies To