Campbell Scientific CS110 Electric Field Meter - Manual (Page 67)

Appendix E. CS110 as a Slow Antenna
E.3 Programming
The following CRBasic program utilizes the slow antenna capability of the
CS110.
'Program to use the CS110 in slow antenna mode (slowant1.cr1).
'Last updated by Jody Swenson on 9/30/05.
PipeLineMode
Const Mult = 85
Public Delta_E
Public Delta_E_mV2500
Public stat(2)
Public E_field
Public Leakage
DataTable(SlowAnt,1,-1)
Sample(1,Delta_E,IEEE4)
EndTable
BeginProg
CS110
(E_field,Leakage,stat(1),250,Mult,0) 'Measure E_field and leakage.
CS110Shutter(stat(2),1) 'Fully open shutter.
Scan(20,msec,0,0)
VoltDiff
(Delta_E,1,mV250,8,False,0,250,Mult,0) 'no input reversal.
VoltDiff (Delta_E_mV2500,1,mV2500,8,False,0,250,Mult,0) 'no input reversal.
If Delta_E = NAN Then
Delta_E = Delta_E_mV2500
EndIf
CallTable SlowAnt
NextScan
EndProg
In the above program the PipeLineMode instruction enables parallel task
processing necessary to complete a scan in 20 ms. The CS110 instruction
following the BeginProg statement provides a measure of the absolute electric
field along with a leakage current compensation value, and is only executed
once. The CS110Shutter instruction can fully open or fully close the shutter,
based on the whether the 2
nd parameter is a 1, or 0, respectively. Two VoltDiff
instructions are used on two different input voltage ranges to provide more
dynamic range in the charge amplifier output measurement.
The CS110 can be programmed to operate as a field meter and then switch to
operate as a slow antenna. For example, efield measurements may be desired
until they exceed an alarm threshold of ±1500 V/m after which slow antenna
(field change) measurements may be desired. The CR1000 operating system
does not allow the Sequential Mode command and the Pipeline Mode
command used in the above example to exist in the same program. For the
CS110 to be able to switch between measuring the electric field with the CS110
instruction and the electric field change in the “slow antenna” mode, the slow
antenna instructions must be run in the Sequential Mode. One way to
accomplish this would be to program the CR1000 to monitor a 1 minute running
average of the efield and when it exceeds ±1500 v/m switch to the slow antenna
mode for a fixed amount of time and then return to the field meter mode.
E-5