Campbell CR800 Dokumentacja Pobierz pdf (Strona 176)

Section 7. Measurement Instructions

ReadIO (Dest, Mask)

ReadIO is used to read the status of selected control I/O channels (ports) on the

CR800. There are 8 ports. The status of these ports is considered to be a binary

number with a high port (+5 V) signifying 1 and a low port (0 V) signifying 0.

For example, if ports 1 and 3 are high and the rest low, the binary representation

is 00000101, or 5 decimal. The mask parameter is used to select which of the

ports to read, it too is a binary representation of the ports, a 1 means pay

attention to the status of the port, a 0 means ignore the status of the port (the

mask is "anded" with the port status; the "and" operation returns a 1 for a digit if

the mask digit and the port status are both 1 and a 0 if either or both is 0).

CRBasic allows the entry of numbers in binary format by preceding the number

with "&B". For example if the mask is entered as &B100 (leading zeros can be

omitted in binary format just as in decimal) and ports 3 and 1 are high as in the

previous example, the result of the instruction will be 4 (decimal, binary = 100);

if port 3 is low, the result would be 0.

Examples

ReadIO(Port3, &B100) ' read port 3 if port 3 is high then

‘Port3 = 4, if port 3 is low then Port3 = 0

SDI12Recorder (Dest, SDIPort, SDIAddress, SDICommand, Multiplier,

Offset)

The SDI12Recorder instruction is used to retrieve the results from an SDI-12

sensor.

Each execution of the SDI12Recorder instruction sends an (address)M! and

then an (address)D0!

M! instructs the sensor to make the measurement; D0! is a request for the data.

See the CRBasic Editor for the detailed description of the parameters and

commands.

VibratingWire (Dest, Reps, Range, SEChan, ExChan, StartFreq, EndFreq,

TSweep, Steps, DelMeas, NumCycles, DelReps, Multiplier, Offset)

The VibratingWire instruction is used to measure a vibrating wire sensor with

a swept frequency (from low to high).

The period of the response is measured and 1/T

is calculated. T is the period

of the measured signal in milliseconds.

Parameter

& Data Type

Enter

Dest

The Dest parameter is a variable in which to store the results of the

measurement.

Reps

The Reps parameter is the number of times the measurement should be made.

Measurements are made on consecutive channels. If the Reps parameter is

greater than 1, the Dest parameter must be a variable array.

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