Specifications

Section 19. Troubleshooting
19-3
experimenting with the InstructionTimes() instruction in the program.
Analyzing InstructionTimes() results can be difficult due to the multitasking
nature of the logger, but it can be a powerful way to fine tune a program.
19.1.4 NAN and ±INF
NAN (not-a-number) and ±INF (infinite) are data words indicating an
exceptional occurrence in datalogger function or processing. NAN is a
constant that can be used in expressions such as in EXAMPLE 19.1-1 NAN
can als
o be used in the disable variable (DisableVar) in output processing (data
storage) instructions.
EXAMPLE 19.1-1. Using NAN in an Expressions
If WindDir = NAN Then
WDFlag = True
Else
WDFlag=False
EndIf
19.1.4.1 Measurements and NAN
NAN results when an instruction fails to return a valid measurement.
Analog Measurements
When NAN results from analog voltage measurements, it indicates an
overrange error wherein the input voltage exceeds the programmed input range.
When NAN occurs with auto ranging, it indicates either the first or second
measurement in the autorange sequence has overranged.
If an analog sensor is open (inputs not connected but “floating”), the inputs
will remain floating near the voltage they were last connected to; a
measurement on ±2.5 mV, ±7.5 mV, ±25 mV, or ±250 mV voltage range will
overrange and return NAN.
To make a differential measurement, voltage inputs must be within the CR1000
common mode range of ±5 V. Otherwise, the CR1000 indicates the overrange
by returning NAN.
SDI-12 Measurements
NAN results when the command issued by the SDI12Recorder() instruction
fails to get a response from an SDI-12 probe.
19.1.4.2 Floating Point Math, NAN, and ±INF
TABLE 19.1-1 lists math expressions, their CRBASIC form, and IEEE floating
point math result loaded into variables declared as FLOAT or STRING.