Campbell Scientific CS110 Electric Field Meter - Manual (Page 30)

CS110 Electric Field Meter
Public variables are defined and available for viewing in the Public table,
which is a data table automatically set up by the CR1000. The Public table
keeps only the current value of each of the defined variables.
In the example program, the DataTable instruction is used to define the data
table Tab1. A record in a table consists of the data from all output processing
instructions, along with a record number and time stamp data. Using -1 for last
parameter in DataTable results in the automatic allocation of all available
table storage area. The DataInterval instruction following the DataTable
instruction defines the interval at which new values are determined and written
into the table, which is every 60 seconds in the above example. Once a table is
full the CR1000 writes new values over the top of old values starting with the
oldest data in the table. Data can be collected manually or automatically on a
scheduled collection interval by means of LoggerNet PC software.
The Sample output processing instruction simply outputs the current variable
value at the appropriate time to the data table. The Average and StdDev output
processing instructions accumulate all measured values over the associated
data interval and then compute the average and standard deviation,
respectively, at the appropriate time. Several other processing instructions exist
for the CR1000 as described in the CR1000 Measurement and Control System
Operator’s Manual.
The Scan and NextScan instructions set up a loop based on the scan interval.
PanelTemp, VoltDiff, Battery, and CS110 are measurement instructions that
return the temperature inside the CS110 case, relative humidity inside the
CS110 case, the voltage being provided to the CS110 to power the instrument
and the measured electric field, respectively. These and other measurement
instructions are discussed more fully in Section 7 on CS110 Measurement
Instructions. The CallTable instruction sends data to the output processing
instructions associated with a given table.
A more involved program that incorporates site correction multiplier, rainfall,
wind speed and direction, solar radiation, relative humidity and air
temperature, along with electric field follows:
'CS110 efield and weather station program.(CS110_WStation.cr1).
'Measures rainfall, wind speed and direction, solar radiation,
'relative humidity and air temperature and electric field.
'Updated last by Jody Swenson on 11/15/05 for Error_Count.
const Mparallel_plate = 85
const Csite = 0.10
const Mcorrected = Mparallel_plate*Csite 'Mcorrected is what goes into CS110 instruction.
Public E_field
Units E_field=volts/m
Public battery_volt
Public leakage_cur
Units leakage_cur=nA
Public status
Public panel_temp
Units panel_temp=DegC
Public rain_fall
Units rain_fall=inch
Public wind_speed
22