Gill Instruments Ltd
3. SYSTEM OPERATION
3.1 Overview
•
Data output rates up to 50s-1.
•
Measurement of wind velocities in excess of 30ms-1 .
•
Wind speed accuracy < 1% RMS.
•
Accurate speed of sound measurement.
•
Configuration carried out via serial port and stored in non-volatile memory.
•
High speed, full duplex RS422 interface, operating up to 115200 baud.
•
Background diagnostics providing the user with the confidence that the unit is operating
correctly.
•
6 differential 14 bit analogue inputs and one PRT100 input.
•
Analogue outputs representing wind speed, SoS, and temperature optionally fitted in
PCI.
3.2 Operating modes
The anemometer has two operating modes:
1.
Measurement mode - This is the normal mode of operation, which is the default
mode from power up.
2.
Interactive mode - This allows the anemometer to be configured and interrogated.
3.3 Measurement Mode
The principle of operation is described in Appendix B. The parameters sampled are determined by
the anemometer’s configuration and consist of:
1.
Wind velocity (axis velocities are always sampled)
2.
Speed of Sound (SoS)
3.
Analogue Inputs (6)
4.
Absolute Temperature (PRT100).
The way in which the results are calculated, formatted and reported depends upon the configuration
of the anemometer.
3.4 Sampling
Wind velocity, SoS and analogue inputs are sampled every 10ms, in a fixed sequential pattern. The
PRT100 is sampled every 40ms. The measurement sequence is shown in Drawing Number 1210-K-
068.
3.5 Averaging
These samples are block averaged before being converted into results. For wind speed, SoS and
analogue inputs the number of samples used in the block average can be set to between 2 and 250
samples. The corresponding maximum number of PRT100 samples per result is 62.
HS-50 Research Anemometer
Page 7
Issue 02
Doc. No. 1199-PS-0032
November 2004
Summary of Contents for HS-50
Page 2: ......
