Sea-Bird Scientific SBE 25plus, User Manual

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The Seasave software uses the real-time output rate from the .xmlcon configuration file
for the 25plus. This must be the same as the output rate set by the sensor.
The Data Processing software uses the information in the file header to get the sample
rate from:
• The .hex file saved in Seasave during real-time data collection
• The file transmitted from the 25plus, at 16 scans/second.
Notes:
• If the flash memory in the 25plus is full, data collection and transmission will continue,
but this data will not be saved. The stored data is not overwritten.
• The 25plus goes into a low-power mode if no command is sent or it does not collect
data for 2 minutes. Push
Enter to put the 25plus into standby mode.
5.4.1 Standard output format
Standard real-time data includes:
• temperature
• conductivity
• pressure
• pressure temperature
• data from enabled voltage sensors.
The 25plus cannot transmit data from serial sensors or diagnostics in real-time. To get
this data, transmit data from the 25plus memory to a PC.
The data format is a combination of fixed-byte size and markers. The fixed byte area
agrees with the core measurements of the 25plus and diagnostic output. The variable
area has serial sensor output, which may be asynchronous.
The example below shows the hexidecimal format.
Notes:
• Seaterm232 always gets all of the selected data from memory in raw hexidecimal
format so that the SBE Data Processing software can use it.
• The pressure sensor is an absolute sensor. The raw output, OutputFormat=0,
includes the effect of atmospheric pressure (14.7 psi), as shown on the Calibration
Sheet. When the output is in engineering units, pressure data is relative to the ocean
surface, at 0 decibars. The sensor uses the equation:
pressure, dbar = (pressure, psia - 14.7) × 0.689476
5.4.1.1 Equations to write user-made software
The software from the manufacturer uses the variables below to process data. The user
can use this information to make data processing software.
In the fixed length area, the 25plus stores data from the T, C, P, eight voltage inputs, and
some diagnostic information. The 24b numbers are stored as 32b numbers with zero
padding. The full string is 36 bytes, or 72 hexidecimal characters. All auxiliary voltage
data is always recorded in memory, even if they are transmitted in real-time.
Location Hex Variable Encoding
b31–b0 tttttttt temperature, Hz IEEE 754 format floating point, 32 bit
Deployment and recovery
25