9 the scan — measurement timing and processing, The scan — measurement timing and processing -46, 1. formats for output data -46 – Campbell Scientific LoggerNet Datalogger Support Software User Manual

Page 264

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Section 7. Creating and Editing Datalogger Programs

The output processing instructions included in a data table declaration

determine the values output in the table. The table must be called by the

program using the CallTable (Tablename) instruction in order for the output

processing to take. That is, each time a new measurement is made, the data

table is called. When the table is called, the output processing instructions

within the table process the current inputs. If the trigger conditions for the data

table are true, the processed values are output to the data table. In the example

below, several averages are output.

Average(Reps, Source, DataType, DisableVar)

Average(1,RefTemp,fp2,0)

Average(6,TC(1),fp2,0)

Average is an output processing instruction that will output the average of a

variable over the output interval. The parameters are repetitions (the number

of elements in an array to calculate averages for), the Source variable or array

to average, the data format to store the result in (TABLE 7-1), and a disable

variable that allows excluding readings from the average if conditions are not

met. A reading will not be included in the average if the disable variable is not

equal to 0; the example has 0 entered for the disable variable so all readings are

included in the average.

TABLE 7-1. Formats for Output Data

Code

Data Format

Size

Range

Resolution

FP2

Campbell Scientific floating point

2 bytes

±

7999

13 bits (about 4 digits)

IEEE4

IEEE four byte floating point

4 bytes

1.8 E -38 to 1.7 E 38

24 bits (about 7 digits)

LONG

4 byte Signed Integer

4 bytes

-2,147,483,648 to

+2,147,483,647

1 bit (1)

7.3.4.9 The Scan — Measurement Timing and Processing

Once the measurements and calculations have been listed and the output tables

defined, the program itself may be relatively short. The executable program

begins with BeginProg and ends with EndProg. The measurements,

processing, and calls to output tables bracketed by the Scan and NextScan

instructions determine the sequence and timing of the datalogging.

BeginProg

Scan(1,MSEC,3,0)

PanelTemp(RefTemp, 250)

TCDiff(TC(),6,mV50,4,1,TypeT,RefTemp,RevDiff,Del,Integ,Mult,Offset)

CallTable Temp

NextScan

EndProg

7-46

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