Precipitation Station Manual V /20/2001

Transcription

1 Precipitation Station Manual V /20/2001 John Porter Deployment The HOBO Event Recorder is initialized using Boxcar 3.6 software. This software is available on a disk for PCs or on the Internet for Macintosh computers ( The serial cable supplied by Onset with the Boxcar software should be connected to a free serial port on the computer you will use. The manual that comes with the software describes its installation. The computer connects to a plug sealed in the film container on the wire coming out the bottom of the rain gauge. Before starting to start a station, make sure that the clock and calendar on the computer are set correctly. To simplify data analysis, they should always be set for EASTERN STANDARD TIME (not Daylight Savings Time). The HOBO Event Recorder automatically reads the date and time from the PC used to start it. To start the station recording, it needs to be launched. To start the logger running, it should be Launched by selecting Launch on the Logger menu.

2 In launching there are 3 key fields. 1. Event name should include the name or location of the station and the units (mm) with no spaces. 2. Event value needs to be set to Lockout after event under Advanced Options needs to be checked and a value of 01 seconds selected. Confirm that the Battery State is Good. If not, replace the battery before launching. The reason it is important that the Event Name include some unique identification of the station location is that once the data is exported into text formats, only the Event Name is written at the top of a data column. If Event Name is generic, it will be impossible to later know which station the data came from. The Event Value and Lockout after event options are needed for the units to be correct (mm) and to avoid false tips. Reading Data To read the data, reconnect the computer to the rain gauge and start Boxcar software. Select Readout from the Logger menu to start the process.

3 Save the file using a name that is descriptive of the station and time. In this case, ST1 is short for Station 1 and 0106 indicates year 2001 and month 06 (June). You are limited to 9 characters in the file name. You will then see a graph that looks something like this. Amounts are cumulative, so plateaus indicate times of no rain and slopes indicate periods of rain. A steep slope indicates intense rain, a shallow slope, slower rainfall.

4 A second window displays the basic information for the session. You can use the Show Data arrow to see the data in textual form (already done in this example) To export the data, hit the Export to Excel button (or choose File/Export/Microsoft Excel from the menu). Hit this button to export the file into an Excel-compatible text format

5 Hit the Export button to continue the process. There are no other options to select here. Select the file name to export the data to. Typically this will be the same name as the data file (e.g. ST1_0106.DTF), but with.txt instead of.dtf appended. The location of each station, along with a copy of the.dtf and.txt files should be sent to the VCR/LTER Information Manager (jhp7e@virginia.edu) for inclusion in the VCR/LTER Data Archive. They can be attached to messages or sent on a floppy disk. Contact the Information Manager if you have additional questions. Construction - Parts?? Davis Rain Collector II Metric (0.2 mm/tip)?? Hobo Event Logger ( 1/8 male and female 3-conductor stereo plugs (Radio Shack parts C and B)?? 35 mm film canister?? Silicon sealant (to waterproof film canister)

6 Construction Make wiring connections as seen in figure 1. In specific, 1. Connect the micro plug already installed through the nipple on the waterproof box of the HOBO unit to the reed switch in the rain collector. You will need to cut the existing telephone-style wire, cut the HOBO wire to length and solder them together. 2. Loosen the nipple on the Hobo Event Recorder and feed through approximately 1 foot (30 cm) of the leftover wire from the telephone-style cable from the precipitation station. Additionally, run the other end of the cable through a hole punched in the bottom of a 35mm film canister. Construct the extender cable by adding male (inside the HOBO Event Recorder) and the female (to the longer end of the cable) connectors. This should be a straight through extender so that the HOBO Event Recorder can be hooked to the computer cable for dumping without needing to remove the event logger from the rain collector. 3. Install the connectors into the appropriate sockets in the HOBO Event Recorder and close its lid. Secure the Hobo Event Recorder to the stanchion of the tipping bucket that is nearest the notch in the bottom of the rain collector that is used for the wire to run out of the collector using electrical tape or other adhesives. Make sure that it will not interfere with the movement of the tipping bucket in any way. 4. If you wish to reduce the risk of insects interfering with the tipping buckets in the rain gauge, you may want to add a perforated container containing mothballs to the rain gauge. Again, make sure it will not interfere with the tipping buckets! 5. Install the station by removing the top and using screws from the inside to attach the base to a horizontal platform. Note that correct readings depend on the station being level, so a carpenter s level should be used to assure that the station is plumb.

7 Orange and Pink Wires Magnetic Reed Switch Red & Black Wires Total wire length approximately 8 White wire to Hobo Micro Plug Black wire to Hobo Micro Plug Figure 1 Hobo Micro Plug 1/8 3- conductor plug, female Downloading plug extender Wires approximately 1 foot long Red wire to tip Pink wire to middle Black wire to body 1/8 3- conductor plug, male