2 voltage – Campbell Scientific CR800 and CR850 Measurement and Control Systems User Manual
Page 270

Section 8. Operation
270
basic code requirements. The DataTime() instruction is a more recent
introduction that facilitates time stamping with system time. See Data Table
Declarations
(p. 453)
and CRBasic Editor Help for more information.
CRBasic Example 62. Time Stamping with System Time
'Declare Variables
Public
value
'Declare data table
DataTable
(Test,True,1000)
Sample
(1,Value,FP2)
EndTable
SequentialMode
BeginProg
Scan
(1,Sec,10,0)
'Delay -- in an operational program, delay may be caused by other code
Delay
(1,500,mSec)
'Measure Value -- can be any analog measurement
PanelTemp
(Value,0)
'Immediately call SlowSequence to execute CallTable()
TriggerSequence
(1,0)
NextScan
'Allow data to be stored 510 ms into the Scan with a s.51 time stamp
SlowSequence
Do
WaitTriggerSequence
CallTable
(Test)
Loop
EndProg
Other time-processing CRBasic instructions are governed by these same rules.
Consult CRBasic Editor Help for more information on specific instructions.
8.1.2 Voltage
The CR800 incorporates a programmable gain input instrumentation amplifier
(PGIA), as illustrated in figure PGI Amplifier
(p. 271).
The voltage gain of the
instrumentation amplifier is determined by the user-selected range code associated
with voltage-measurement instructions. The PGIA can be configured to measure
either single-ended (SE) or differential (DIFF) voltages. For SE measurements,
the voltage to be measured is connected to the H input while the L input is
internally connected to signal ground (
). CRBasic instructions BrHalf(),
BrHalf3W(), TCSE(), Therm107(), Therm108(), Therm109(), and VoltSE()
perform SE voltage measurements. For DIFF measurements, the voltage to be
measured is connected between the H and L inputs on the PGIA. CRBasic