SonTek/YSI Argonaut-XR Technical Manual - HydroScientific West

3.2. The Paroscientific Digiquartz (PAROSFREQ)
Using Frequency Pressure Sensors with SonTek/YSI Systems (June 2001)
SonTek/YSI
User requirements for deeper ratings (compared to DRUCK) and faster response (compared to
PAROS) convinced SonTek to offer the Paroscientific digiquartz sensor with frequency output
(PAROSFREQ). Functionally, the interface for the PAROSFREQ is identical to the interface for the
DRUCK, as both are frequency-based sensors. The PAROSFREQ sensors are available for ADP,
PC-ADP, and Hydra systems. The differences, when compared with a strain-gage sensor, are as
follows:
• The PAROSFREQ is an absolute sensor. It reads 1 dbar in air; a strain gage reports 0 dbars.
• Requires a special interface to sample the frequency signal.
• Requires a special frequency splitter cable.
• Sampling rate is limited to 10 Hz (ADVs and Hydras) because of the time required to sample
the frequency signal with sufficient precision.
• Requires a calibration (specific to each sensor) to be loaded into the processor (system CPU
or a user PC) to obtain valid pressure readings.
• Available in 50-psia (≈22 dbar strain gage) and 100-psia (≈60-m strain gage) pressure ratings.
The structure of the calibration file corresponding to the PAROSFREQ sensor is similar to the
DRUCK. For historic reasons, PAROSFREQ calibration file uses the .drk extension.
• Pressure Sensor Serial Number
• Oscillator Frequency (in Hz)
• U0
• N/A
• N/A
• N/A
• N/A
• Y1 Y2 Y3 N/A
• C1 C2 C3 N/A
• D1 D2 N/A N/A
• T1 T2 T3 T4
• N/A N/A N/A N/A
• N/A N/A N/A N/A
Example – Paroscientific calibration file p68888.drk:
P68888
12.0000000E+06
5.880670
0.0
0.0
0.0
0.0
-3898.415 -10940.31 0.0 0.0
224.5927 6.013600 -245.2861 0.0
0.041219 0.0 0.0 0.0
27.94067 0.859765 20.65914 26.99304
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
Note: The U, Y, C, D, and T coefficients can
be found on the Paroscientific calibration sheet.
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