Moored Profiler CTD & Optional DO Sensor
SBE 52-MP

The SBE 52-MP is a conductivity, temperature, depth (pressure) sensor (CTD), designed for moored profiling applications in which the instrument makes vertical profile measurements from a device that travels vertically beneath a buoy, or from a buoyant sub-surface sensor package that is winched up and down from a bottom-mounted platform. The 52-MP incorporates pump-controlled, TC-ducted flow to minimize salinity spiking. On typically slow-moving packages (e.g., 20 - 50 cm/sec), its sampling rate of once per second provides good spatial resolution of oceanographic structures and gradients. The 52-MP can optionally be configured with a Dissolved Oxygen Sensor Module (SBE 43F), as shown in the photo. The SBE 43F is a frequency-output version of our SBE 43 Dissolved Oxygen Sensor, and carries the same performance specifications.

The SBE 52-MP uses the same accurate and stable thermistor, conductivity cell, and pressure sensor that are used in the MicroCAT and ARGO Float products. It is easy-to-use, compact, and ruggedly made of titanium and other low-maintenance (plastic) materials. The operating commands are easy to execute with a third-party data logger or your own acquisition system.. EEPROM-stored calibration coefficients permit data upload in ASCII engineering units (mmho/cm, degrees C, decibars, ml/l). Alternatively, the user can select to upload data in hexadecimal or binary. The SBE 52-MP is externally powered, and temporarily stores data in static RAM memory. If/when power is removed, any data stored in memory is lost.

SAMPLING MODES

The SBE 52-MP has two sampling modes:

• Autonomous sampling -- On command, the 52-MP begins autonomous sampling. The 52-MP runs continuously, sampling at one scan per second (1 Hz). It stores the data in memory, and can also transmit in real-time. It can bin average the data, and store the bin averaged data in memory in addition to the unaveraged data. On command (typically at the end of each profile), data is uploaded to the moored profiler.
• Polled sampling -- On command, the 52-MP takes one sample (CTD, DO) and transmits the data in real-time.

• Improved conductivity and oxygen response -- The pump brings a new water sample into the system at a constant flow rate, fixing the sensors' time constants to ensure maximum dynamic accuracy, and flushes the previously sampled water from the conductivity cell and oxygen sensor plenum. For polled sampling, pump run time for best DO accuracy is a function of temperature and pressure, and is automatically determined by the 52-MP (55 seconds, maximum).
• Reduced fouling -- When not sampling, the U-shaped flow path and pump impeller restrict flow, maintaining an effective concentration of anti-foulant inside the conductivity cell to minimizing fouling.

CONFIGURATION

A standard SBE 52-MP is supplied with:

• Titanium housing for depths to 7000 meters (22,900 feet)
• Conductivity, temperature, and pressure (offered in eight full scale ranges from 20 to 7000 dbars) sensors
• Integrated T-C Duct and internal pump for flow-controlled conductivity, temperature, and dissolved oxygen sensor response
• Anti-foulant fittings and expendable anti-foulant devices
• RS-232 or logic level (0-3.3V) interface (factory configured)
• XSG 4-pin I/O bulkhead connector
• IE-55 bulkhead connector for optional SBE 43F Dissolved Oxygen Sensor
• 3/8-16 locator/mounting hole in the sensor end cap, to assist in mounting to a McLane MMP moored profiler

Options include:

• Plastic housing for depths to 600 meters
• SBE 43F Dissolved Oxygen Sensor (frequency-output version of our SBE 43 Dissolved Oxygen Sensor)
• Wet-pluggable MCBH connector in lieu of standard (XSG) I/O connector

SOFTWARE

The SBE 52-MP is supplied with a Win 95/98/NT/2000/XP software package, SEASOFT©-Win32, which includes SEATERM, a terminal program for instrument setup and data display.

SPECIFICATIONS

Power Requirements:
Input power -- 3 Watts at 7-16 VDC (consult factory for voltage outside this range)
Turn-on transient -- 300 mA at 10 V
Quiescent (sleep) state -- 0.008 mA at 10 V
Awake but not sampling -- 5.2 mA at 10 V
Sampling (includes pump) -- 62 mA at 10 V

Memory:
Static RAM; stores up to 28,000 samples of conductivity, temperature, pressure, and dissolved oxygen data.
Note: If external power is removed, any data in memory is lost.

Housing Material and Depth Rating:
Standard  3AL/2.5V Titanium, 7000 meters (22,900 feet)
Optional  Plastic, 600 meters (1960 feet)

Weight:
Standard titanium housing
   In air  5.3 kg (11.8 lbs)
   In water  3.7 kg (8.2 lbs)

(DO sensor cable not shown for clarity)