Vaisala PTB210 SERIES Manuel d'instructions télécharger pdf (Page 39)

Variable data types are STRING and the numeric types: FLOAT, LONG and

BOOLEAN. In the program sequence of the automatic weather station the data

types IEEE4 an STRING are to be used. The example below points this out.

Public T107_C(2)

Public AirPressString AS STRING * 30

In this case the T107_C(2) variable is a simple array of two temperature measure-

ments with IEEE4 standard as data type where the STRING data type is put in

because of the need to transmit simple text commands through a serial line for

operating the digital pressure sensor PTB210. As a result serial data are received

in terms of pressure readings at a individual conﬁgured port of the data logger.

The numeric expression *30 represents the maximum of text characters to be sent

depending on the length of the required command.

Units

Every variable stored in the tables is assigned to its engineering unit as shown below.

Units Temp_C = Deg C

Units Humid_C = %

Units WindSpd = m/s

Units Pyrano = W/m^2

Units AirPress = hPa

Thus, it is easier to handle data for future interpretations or calculations for people

who do not know about the source code of storage process. Units are strictly for

documentation. The CR1000 makes neither use of them nor checks on their accuracy.

Constants

A constant can be declared at the beginning of a program to assign an alphanumeric

name to be used in place of a value so the program can refer to the name rather

than the value itself. Using a constant in place of a value can make the program

easier to be read and to be modify and more secure against unintended changes.

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Vaisala PTB210 SERIES Manuel d'instructions Page 39