Sub-Scans; Burst Measurements - Campbell GRANITE VOLT Series Product Manual

10.4.1.1 Sub-scans

To measure at rates faster than the maximum scan rate of the data logger, the
()/NextSubScan
the measurement speed is dictated by the SubInterval and Units parameters.
The following program makes 20
the notch frequency chosen must accommodate the SubScan rate. In this example, f
500 or greater to allow for a single-ended measurement in a 5 ms SubScan. Refer to
16) for analog voltage measurement speeds associated with f
'Program Example: Measuring VoltSE() in a Sub-Scan
Public FastSE(20)
Dim 'index counter
i
DataTable
(FastSETable,True,-1)
Sample (20,FastSE(),FP2)
EndTable
BeginProg
Scan (1,sec,10,0)
'initialize index counter
i=1
SubScan (5,msec,20)
CDM_VoltSe
i = i + 1
NextSubScan
CallTable FastSETable
NextScan
EndProg

10.4.1.2 Burst measurements

To measure at rates greater than the maximum sub-scan rate of the data logger, switch the
measurement into burst mode by negating the measurement channel parameter. In burst mode,
the measurement dwells on a single channel and measures it at rates up to 30 kHz, as
demonstrated in the following CRBasic example . Burst measurements do not allow offset
measurement, input reversal, or excitation reversal.
The measurement rate is determined by the notch frequency (f
measurement is made at 15 kHz. User-entered notch frequencies will be rounded to the nearest
notch-frequency option (see
options). The destination parameter must be an array sized to the total number of measurements
to be made. Refer to the GRANITE 6 CRBasic Help for more information. The following program
makes 1,735 CDM_VoltSE()
instruction pair is added within the data logger scan. Using this method,
CDM_VoltSE()
CRBasic Example 2: Measuring VoltSE() in a sub-scan
'repeat the 200 Hz measurement 20 times
(VOLT108,1,FastSE(i),1,mV5000,1,False,150,500,1,0)
'increment index counter after each measurement
Table 8-2 (p. 16) or the CRBasic Help for a full list of frequency
measurements on SE 1 at a rate of 15 kHz.
measurements on SE 1 at 200 Hz. Note that
options.
N1
). With f
N1
SubScan
must be
N1
Table 8-2
set to 15000, the
N1
VOLT 100 series
(p.
35