Campbell Scientific CR1000 Measurement and Control System - Manual (Page 233)

Section 7. Installation
233
BeginProg
Scan (1,Sec,0,0) '<<<<Measurement rate is determined by Interval and Units
VoltSe (FastSE(),1,mV2_5,1,False,100,250,1.0,0)
CallTable FastSETable
NextScan
EndProg
By modifying the Interval , Units , and Buffers arguments, VoltSE() can be
executed at 100 Hz at 100% duty cycle. The following program measures 16
analog input channels at 100 Hz.
Table 34. CRBasic EXAMPLE. Measuring VoltSE() at 100 Hz
PipeLineMode '<<<<Pipeline mode ensures precise timing of measurements.
Public FastSE(16)
DataTable (FastSETable,1,-1)
Sample (16,FastSE(),FP2)
EndTable
BeginProg
Scan (10,mSec,10,0) '<<<<Measurement rate is determined by Interval, Units, and Buffers
VoltSe (FastSE(),16,mV2_5,1,False,100,250,1.0,0)
CallTable FastSETable
NextScan
EndProg
7.8.12.2 Measurement Rate: 101 to 600 Hz
To measure at rates between 100 and 600 Hz, the SubScan() / NextSubScan
instruction pair is added. Measurements over 100 Hz do not do not have 100%
duty cycle, but are accomplished through measurement bursts. Each burst lasts
for some fraction of the scan interval. During the remainder of the scan interval,
the CR1000 processor catches up on overhead tasks and processes data stored in
the buffers. For example, the CR1000 can be programmed to measure VoltSE()
on 8 channels at 200 Hz with a 95% duty cycle as follows:
Table 35. Measuring VoltSE() at 200 Hz
PipeLineMode '<<<<Pipeline mode ensures precise timing of measurements.
Public BurstSE(8)
DataTable (BurstSETable,1,-1)
Sample (8,BurstSE(),FP2)
EndTable
BeginProg
Scan (1,Sec,10,0) '<<<<Buffers added
SubScan (5,mSec,190) '<<<<Interval, Units, and Count determine speed and number of measurements
VoltSe (BurstSE(),8,mV2_5,1,False,100,250,1.0,0)
CallTable BurstSETable
NextSubScan
NextScan
EndProg