Section 4. Sensor Support
43
Note:
The PulseCount () instruction should not be used in a conditional
statement or subroutine. To ensure all pulses are detected, it must be executed
each scan.
Execution of PulseCount () within a scan involves determining the accumulated
counts in each dedicated 16-bit counter since execution of the last PulseCount
(). PulseCount () parameter (POption) determines if the output is in counts
(POption = 0) or frequency (POption = 1). Counts are the preferred output
option for measuring number of tips from a tipping bucket rain gage, or the
number of times a door opens. Many pulse sensors, such as anemometers and
flow meters, are calibrated in terms of frequency (Hz or counts / second), and
are usually measured with the frequency option.
Resolution of the pulse counters is one count. Resolution of frequency is
(1/scan interval). For example, the frequency resolution of PulseCount()
returning a result every 1 second is 1 Hz. The resultant measurement will
bounce around by the resolution. For example, if you are scanning a 2.5 Hz
input once a second, in some intervals there will be 2 counts and in some 3. If
the pulse measurement is averaged, the correct value will be the result.
Accuracy is limited by a small scan interval error of ±(3 ppm of scan in
10 µs) plus the measurement resolution error of ± 1 Hz. The sum is essentially ±
1 Hz. Extending a 1 second measurement interval to 10 seconds, either by
increasing the scan interval or by averaging, improves the resulting frequency
resolution from 1 Hz to 0.1 Hz. Averaging can be accomplished by the Average
() instruction or by computing a running or spatial average through
programming.
4.4.1
Pulse input Channels
Read More! Review
pulse counter specifications
p. 35. Review pulse counter
programming in CRBASIC Help for the PulseCount () instruction.
Summary of Contents for CR200
Page 32: ...Section 2 Quickstart Tutorial 22 ...
Page 45: ...Section 3 Overview 35 3 3 Specifications ...
Page 46: ...Section 3 Overview 36 ...
Page 58: ...Section 4 Sensor Support 48 ...
Page 62: ...Section 5 Measurement and Control Peripherals 52 ...
Page 78: ...Section 8 CR200 X Configuration 68 ...
Page 102: ...Section 9 Programming 92 ...
Page 138: ...Section 11 Programming Resource Library 128 ...
Page 156: ...Section 16 Support Software 146 ...
Page 160: ...Section 17 Care and Maintenance 150 ...
Page 167: ...Section 18 Troubleshooting 157 18 3 3 2 Charging Circuit Test Solar Panel ...
Page 168: ...Section 18 Troubleshooting 158 18 3 3 3 Charging Circuit Test Transformer ...
Page 169: ...Section 18 Troubleshooting 159 18 3 3 4 Adjusting Charging Circuit Voltage ...
Page 170: ...Section 18 Troubleshooting 160 ...
Page 184: ...Appendix A Glossary 14 ...
Page 190: ...Appendix B Status Table and Settings 20 ...
Page 192: ...Appendix C Serial Port Pin Outs 22 ...
Page 211: ......