Casella-cel Tipping bucket rain gauge Instrukcja Użytkownika Pobierz pdf (Strona 12)

6. COUNTING THE BUCKET TIPS

A variety of devices may be used to count the bucket tips, these include:

¤ Data Loggers (with contact closure input capability),

¤ Event counter (a simple LCD counter to indicate bucket tips),

¤ Chart Recorder,

¤ Computer data acquisition system.

Consideration should be given to ensure that the counting/logging device

used can accept a contact closure input.

For fast counter inputs, some form of capacitor-resistor filtering may be

necessary to reduce “bounce” effects in the contact signal.

For details of suitable logging devices please contact the Casella CEL sales

department.

6.1 Reed Switch Details

Switching contact closure time is typically less than 100 milli-seconds for 0.2

mm of rain (N.B. closure time will be faster for 0.5 mm of rain).

Maximum current rating 300 mA

Breakdown voltage 200 V D.C. minimum

Contact resistance 150 mΩ

Insulation resistance 10

Ω

Capacitance open contacts 0.2 pF

Life 10

operations.

Reed switch connections are made via a 2 way terminal block (see Figure 5).

Counting

Figure 5: Connections for reed switch

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Casella-cel Tipping bucket rain gauge Instrukcja Użytkownika Strona 12