Campbell CR6 Series, Руководство оператора

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Section 8. Operation
419
o Settle: User input in µS; default of 0 = 500 µS with minimum of 100
µS
o Fnotch: reciprocal of what we used to call integration time
•
Pipeline differential without reversal with Fnotch=50 Hz or 2 0mS for
our first example: adding this all up you would get 6.00 + .850 + .500 +
20 = 27.35mS. With input reversal, you get to skip the Sync time on the
reverse measurement so it would be coming in at 27.35 + .85 + .500 + 20
= 48.7mS.
•
If in Sequential mode, the above is true except that every new
measurement instruction will be preceded by the Sync (calibration time).
Reps on the same instruction would work as shown in Pipeline mode
where the Sync is only done once.
•
Burst mode is designated by a “-“ prefix on the measurement terminal.
–U1 for example would be used for a burst measurement on U1. When
executed in the datalogger, the Sync+Flush+Fnotch is used for the
first measurement but then the reps are used as the number of samples to
take on that terminal and the Fnotch is the time between
measurements on that terminal.
FIGURE 88: Simplified voltage measurement sequence. Because the
CR6 uses digital signal processing (DSP) to make voltage
measurements, integration and A to D measurement are actually
combined functions. Effective integration time equals 1/fN1, fN1
being the "digital filter" entered into the measurement instruction.
Voltage measurements are made using a 24 bit delta-sigma
A-to-D
(p. 573)
converter with oversampling and digital signal processing ( DSP
(p. 581))
to achieve
an effective resolution approaching 24 bits. Prior to the ampify and settle, a high
impedance programmable-gain instrumentation amplifier (PGIA) amplifies the
signal. See figure
Programmable Gain Input Amplifier (PGIA)
(p. 420).
The
CRBasic program controls amplifier gain and configuration — either single-ended
input or differential input. Internal multiplexers route individual terminals to the
PGIA.
Timing
(p. 210)
of measurement tasks is precisely controlled. The measurement
schedule is determined at compile time and loaded into memory.