Campbell Scientific 52202 52202 Electrically Heated Rain and Snow Gage - Page 14

52202 Electrically Heated Rain and Snow Gage 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 when the bucket is balanced. 7. Maintenance The rain gage should be inspected periodically. Accumulated dirt and debris should be cleaned from funnel, screen and bucket assembly. Electrical connections should be inspected and cleaned. Leveling screws may be readjusted at this time. Periodic recalibration may be desirable to ensure measurement accuracy. The following calibration check is advised every 12 months. 1. With the rain gage properly leveled, slowly pour a measured volume of water into the collection funnel. The rate should be about 10 ml per minute which is approximately 1-in. per hour. The bucket should tip five times for each 10 ml of water. For example, 100 ml should give a count of 50 ±1. Bucket tips may be counted manually or with a counter connected to the rain gage terminals. 2. If the count shows an error of more than 2%, adjust the calibrating screws to correct the error. Raise the screws if the count is low, lower the screws if the count is high. Always adjust both screws equally. 10