Campbell TE525 Instrukcja Obsługi Pobierz pdf (Strona 18)

TE525 Tipping Bucket Rain Gage

8. Operation

8.1 Sensor Schematic

FIGURE 8-1. TE525-series Rain Gage Schematic

8.2 Measurement

Campbell Scientific dataloggers measure TE525 rain gages by counting switch

closures and converting the total to rainfall. The PulseCount() instruction

employs dedicated pulse count accumulators, which continuously monitor the

input signal, even when the datalogger is between program scans. To create a

pulse, an internal 100 kΩ pull-up resistor pulls the pulse input to 5 Vdc when

the switch is open, and a switch closure to ground pulls the input to 0 Vdc.

8.3 Long Cable Lengths

Long cables have appreciable capacitance between lines. A built-up charge

could cause arcing when the switch closes, shortening switch life. A 100 Ω

resistor is connected in series at the switch to prevent arcing by limiting current

(FIGURE 8-1). Campbell Scientific installs this resistor on all current rain

gages.

9. Troubleshooting and Maintenance

All factory repairs and recalibrations require a returned material

authorization (RMA) and completion of the “Declaration of

Hazardous Material and Decontamination” form. Refer to the

Assistance page at the beginning of this manual for more

information.

9.1 Troubleshooting

Symptom: No Precipitation

1. Check that the sensor is wired to the pulse channel specified by the

PulseCount() instruction.

2. Verify that the Configuration Code (switch closure) and Multiplier

parameters for the PulseCount() instruction are correct for the datalogger

type.

3. Disconnect the sensor from the datalogger and use an ohm meter to do a

continuity check of the switch. The resistance measured at the terminal

block on the inside of the bucket between the black and white leads

should vary from infinite (switch open) when the bucket is tipped, to less

than an ohm (switch closed) when the bucket is balanced.

NOTE

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Campbell TE525 Instrukcja Obsługi Strona 18