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on the pressure housing. Without internal amplifier the sensors must be connected to the
in-situ amplifier which is connected to the bulk-head connector via a cable.
6.4 Sensors for the Field DataLogger Mini
The FDL Mini can be equipped with sensors for O
2
, H
2
, H
2
S, NO, N
2
O and STOX on
amperometric channels and electrodes for pH and redox on potentiometric channels. The
sensors can in the standard version be deployed down to 50 m and in the deep-sea version
down to 6000 m. Only the N
2
O sensor is not available in a deep-sea version.
Furthermore, temperature is logged continuously with all other data from a sensor mounted
inside the pressure housing.
NOTE:
Polarization of the sensors must be set for each channel individually from within
SensorTrace Logger. This must be done BEFORE mounting the sensors! Wrong polarization
may destroy the sensor! For setting polarization see 7.3.1
Setting polarization
6.5 Charging and battery
Battery life time is about 3 months at 25 °C
Charging time is about 5 hours
Battery state can be seen in the Unisense Logger software. See 7.3.4
Checking battery level
and storage capacity.
6.6 Computer connection
The PC communication cable (MDL-COM001) connected to the communications bulkhead
connector at the non-sensor end of the FDL Mini allows communication between the FDL
Mini and a computer. Using the SensorTrace Logger software the settings of the FDL Mini
may be changed, logged data may be downloaded, and the instrument may be used online.
6.7 Logging capabilities
The FDL Mini comes with 8 GB (micro SD) of data storage capacity. 24 hours logging of the
signal from four sensors at 1 data point per second gives 2.3 MB corresponding to more
than 3000 days of data storage capability with 8 GB memory.
The FDL Mini can log data at five different intervals: 1 sec., 10 sec. or 60 sec.
All channels will log at the same frequency.
6.8 Connection with external units
The FDL Mini can send data in real time to
external units such as CTD’s or ADV’s
using RS-
232 or RS-485 serial protocols. The serial protocol allows that the external unit can poll the
FDL Mini for getting the last data point. Only one of these serial standards (RS-232 or RS-
485) is supported on one instrument and must be chosen at the time of ordering. Please