Campbell CR850 User Manual

Section 7. Installation
211
the sensor sends multiple strings at once, consider declaring a single string
variable and read incoming strings one at a time.
TheCR800adjuststhedeclaredsizeofstrings.Onebyteisalwaysadded
tothedeclaredlength,whichisthenincreasedbyuptoanotherthree
bytestomakelengthdivisiblebyfour.
Declaredstringlength,notnumberofcharacters,determinesthe
memoryconsumedwhenstringsarewrittentomemory.Consequ
ently,
largestringsnotfilledwithcharacterswastesignificantmemory.
7.8.8.5.6 Demonstration Program
CRBasic example Receiving an RS-232 String
(p. 211) is provided as an exercise in
serial input / output programming. The example only requires the CR800 and a
single wire jumper between COM1 Tx and COM2 Rx. The program simulates a
temperature and relative humidity sensor transmitting RS-232 (simulated data
comes out of COM1 as an alpha-numeric string).
CRBasicExample40. ReceivinganRS‐232String
'To demonstrate CR800 Serial I/O features, this program simulates a serial sensor
'by transmitting a serial string via COM1 TX. The serial string is received at
'COM2 RX via jumper wire. Simulated air temperature = 27.435 F, relative humidity = '56.789%.
'Wiring:
'COM1 TX (C1) ----- COM2 RX (C4)
'Serial Out Declarations
Public TempOut As Float
Public RhOut As Float
'Declare a string variable large enough to hold the output string.
Public SerialOutString As String * 25
'Serial In Declarations
'Declare a string variable large enough to hold the input string
Public SerialInString As String * 25
'Declare strings to accept parsed data. If parsed data are strictly numeric, this
'array can be declared as Float or Long
Public InStringSplit(2) As String
Alias InStringSplit(1) = TempIn
Alias InStringSplit(2) = RhIn
'Main Program
BeginProg
'Simulate temperature and RH sensor
TempOut = 27.435 'Set simulated temperature to transmit
RhOut = 56.789 'Set simulated relative humidity to transmit

Campbell CR850 Specifications

General

Brand	Campbell
Model	CR850
Category	Measuring Instruments
Language	English