Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 139)

Section 7. Measurement Instructions
7-13
Parameter
& Data Type Enter
SettlingTime
Constant
The time in microseconds to delay between setting up a measurement (switching to the
channel, setting the excitation) and making the measurement. (1 microsecond resolution)
Entry Voltage Range Integration Settling Time
0 ± 20 mV Flash 200 µS (default)
0 All but ± 20 mV, Flash 100 µS (default)
0 All 250 µS 200 µS (default)
0 All _50Hz, _60 Hz 3 mS (default)
>=100 All All µS entered
Integ The time spent on integration in microseconds for each of the channels measured.
Constant Entry Integration
0, 200 Flash Conversion; 200 = 2 flash conversions 100 µS apart
and averaged
250; 500-16000 250 µS; multiples of 500: 250 µS integrations starting each
500 µS and averaged
_60Hz or 16667 16,667 µS (reject 60 Hz noise)
_50 Hz or 20000 20,000 µS (reject 50 Hz noise)
Mult, Offset
Constant,
Variable,
Array, or
Expression
A multiplier and offset by which to scale the raw results of the measurement.
7.6 Excitation/Continuous Analog Output
ExciteCAO (CAOChan, CAOmV, Boost, FastUpdate)
ExciteCAO sets the voltage of a Continuous Analog Output channel.
The datalogger has two continuous analog out (CAO) channels. These
channels are used to provide a continuous analog output. The output may be
used for proportional control. The CAO channels can source 15 mA and sink
5 mA. If Boost is enabled, sink is increased to 15 mA.
To ensure the CAO voltage settles to with in the ±10 mV accuracy
specification of the CAOmV value, a settling time of ten time constants
(~2.6 ms) is required. This time is required for the worst case voltage changes
(e.g., -5000 to +5000 mV). In instances where the change in CAO voltage
from one scan to the next is small and the time required for measurements is
approaching the scan time, the FastScan parameter can be used to shorten the
execution time. When FastScan is true the settling time is shortened to
approximately one time constant and the time required to execute the
instruction to approximately 300
µs. In one time constant the signal settles to
63% of the step change which will not be within ±10 mV for large steps.