PWS100 Present Weather Sensor - Campbell Scientific
PWS100 Present Weather Sensor - Campbell Scientific
PWS100 Present Weather Sensor - Campbell Scientific
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Section 5. Specifications<br />
The particle buffer is able to hold raw data for 500 typical particles. The<br />
processor is able to process the particles at a rate of 120 particles per second,<br />
typically. This means if more than 120 particles per second fall through the<br />
sample volume of 40 cm 2 the particle buffer will start to fill up. If the rain rate<br />
exceeds 120 particles per second for a prolonged period, the buffer could run<br />
out of space and particles will be lost.<br />
The fact that the processor is running behind real-time and/or particles are<br />
being missed can be monitored in the alarm message which can be selected for<br />
data output.<br />
The particle processor then places data about each particle in the Large Particle<br />
Array (LPA). The LPA is 100000 records long. It uses 5 records every 10<br />
seconds plus a record for every processed particle that passes through the<br />
volume. For example if 20 particles per second are processed then 20.5 records<br />
are used per second. Since 100000 records can be stored, the system can store<br />
100000 / 20.5 = 4878 seconds worth of data in the LPA. The user needs to be<br />
aware of the size of this buffer as it is used to hold data that is processed when<br />
a message is output. The size of the buffer may become a limiting factor if a<br />
very long message interval is selected and rainfall rates are high.<br />
The <strong>PWS100</strong> has the capability to store measured data in a buffer called the<br />
message storage buffer, which is 1 MB (1000000 characters) in size. All ASCII<br />
characters including CrLf must be included in any storage calculations. This<br />
buffer stores the user defined messages (see Section 7.5, Message Related<br />
Commands for the types of messages available to the user). A typical message<br />
containing 120 characters can be stored 1000000 / 120 = 8333 times which at<br />
minute intervals for the data output would be over 138 hours worth of storage.<br />
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