Campbell-scientific CR3000 Micrologger Instrukcja Użytkownika Pobierz pdf (Strona 432)

100

101

Section 10. Troubleshooting

432



results can be difficult due to the multitasking nature of the logger, but it can be a

useful tool for fine tuning a program.

10.3.4 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 as shown in CRBasic example Using NAN in Expressions

(p.

432).

. NAN can also be used in conjunction with the disable variable (DisableVar)

in output processing (data storage) instructions as shown in CRBasic example

Using NAN to Filter Data

(p. 434).

10.3.4.1 Measurements and NAN

A NAN indicates an invalid measurement.

10.3.4.1.1 Voltage Measurements

The CR3000 has the following user-selectable voltage ranges: ±5000 mV, ±1000

mV, ±200 mV, ±50 mV, ±20 mV. Input signals that exceed these ranges result in

an over-range indicated by a NAN for the measured result. With auto range to

automatically select the best input range, a NAN indicates that either one or both

of the two measurements in the auto-range sequence over ranged. A voltage input

not connected to a sensor is floating and the resulting measured voltage often

remains near the voltage of the previous measurement. Floating measurements

tend to wander in time, and can mimic a valid measurement. The C (open input

detect/common-mode null) range-code option can be used to force a NAN result

for open (floating) inputs.

10.3.4.1.2 SDI-12 Measurements

NAN is loaded into the first SDI12Recorder() variable under these conditions:

• When busy with terminal commands.

• When the command is an invalid command.

• When the sensor aborts with CR LF and there is no data.

CRBasic EXAMPLE. Using NAN in Expressions

CRBasicExample69. UsingNANinExpressions

If WindDir = NAN Then

WDFlag = False

Else

WDFlag = True

EndIf



10.3.4.2 Floating-Point Math, NAN, and ±INF

Table Math Expressions and CRBasic Results (p. 433) lists math expressions, their

CRBasic form, and IEEE floating point-math result loaded into variables declared

as FLOAT or STRING.

1 2 ... 427 428 429 430 431 432 433 434 435 436 437 ... 589 590

Komentarze do niniejszej Instrukcji

Brak uwag

Campbell-scientific CR3000 Micrologger Instrukcja Użytkownika Strona 432

Komentarze do niniejszej Instrukcji

Powiązane produkty i podręczniki dla Urządzenia pomiarowe Campbell-scientific CR3000 Micrologger