Campbell Scientific CR6 CR6 Measurement and Control System - Page 198

Data Output: Using Data Type Bool8

Page 198 highlights

Section 7. Installation 'Measure thermocouple TCDiff(AirTempC,1,mV200C,U1,TypeT,PTemp,True,0,15000,1.0,0) 'calculate the difference in air temperature and panel temperature deltaT = airtempC - PTemp 'When the difference in air temperatures is >=3 turn LED on and trigger the faster of 'the two data-table intervals. If deltaT >= 3 Then PortSet(4,true) int_fast = true int_slow = false Else PortSet(4,false) int_fast = false int_slow = true EndIf 'Call output tables CallTable TwoInt NextScan EndProg 7.9.9 Data Output: Using Data Type Bool8 Variables used exclusively to store either True or False are usually declared As Boolean. When recorded in final memory, the state of Boolean variables is typically stored in final memory Boolean data type. Boolean data type uses the same four-byte integer format as does data type Long. If final memory or telecommunication band width is at a premium, consider using data type Bool8 instead. BOOL8 is a one-byte variable that holds eight bits of information (8 states * 1 bit per state). To store the same information using the 32-bit BOOLEAN data type, 256 bits are required (8 states * 32 bits per state). When programming with BOOL8 data type, repetitions in the output processing DataTable() instruction must be divisible by two, since an odd number of bytes cannot be stored. Also note that when the CR6 converts a LONG or FLOAT data type to BOOL8, only the least significant eight bits of the binary equivalent are used, i.e., only the binary representation of the decimal integer modulo divide (p. 501) 256 is used. Example: Given: LONG integer 5435 Find: BOOL8 representation of 5435 Solution: 5435 / 256 = 21.2304687 0.2304687 * 256 = 59 Binary representation of 59 = 00111011 (CR6 stores these bits in reverse order) When datalogger support software (p. 89) retrieves the BOOL8 data type, it splits it apart into eight fields of -1 or 0 when storing to an ASCII file. Consequently, more memory is required for the ASCII file, but CR6 memory is conserved. The compact BOOL8 data type also results in less use of telecommunication band width when data are collected. 198

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Section 7.
Installation
'Measure thermocouple
TCDiff
(AirTempC,1,mV200C,U1,TypeT,PTemp,True,0,15000,1.0,0)
'calculate the difference in air temperature and panel temperature
deltaT = airtempC - PTemp
'When the difference in air temperatures is >=3 turn LED on and trigger the faster of
'the two data-table intervals.
If
deltaT >= 3
Then
PortSet
(4,true)
int_fast = true
int_slow = false
Else
PortSet
(4,false)
int_fast = false
int_slow = true
EndIf
'Call output tables
CallTable
TwoInt
NextScan
EndProg
7.9.9
Data Output: Using Data Type Bool8
Variables used exclusively to store either
True
or
False
are usually declared
As
Boolean
.
When recorded in final memory, the state of Boolean variables is
typically stored in final memory Boolean data type.
Boolean data type uses the
same four-byte integer format as does data type Long.
If final memory or
telecommunication band width is at a premium, consider using data type Bool8
instead.
BOOL8 is a one-byte variable that holds eight bits of information (8
states * 1 bit per state).
To store the same information using the 32-bit
BOOLEAN data type, 256 bits are required (8 states * 32 bits per state).
When programming with BOOL8 data type, repetitions in the output processing
DataTable()
instruction must be divisible by two, since an odd number of bytes
cannot be stored.
Also note that when the CR6 converts a LONG or FLOAT data
type to BOOL8, only the least significant eight bits of the binary equivalent are
used, i.e., only the binary representation of the decimal integer
modulo divide
(p.
501)
256 is used.
Example:
Given: LONG integer 5435
Find: BOOL8 representation of 5435
Solution:
5435 / 256 = 21.2304687
0.2304687 * 256 = 59
Binary representation of 59 = 00111011 (CR6 stores these
bits in reverse order)
When
datalogger support software
(p. 89)
retrieves the BOOL8 data type, it splits it
apart into eight fields of
-1
or
0
when storing to an ASCII file. Consequently,
more memory is required for the ASCII file, but CR6 memory is conserved.
The
compact BOOL8 data type also results in less use of telecommunication band
width when data are collected.
198