B&B Electronics 4 Channel Input Buffer Board SDAIBB Uživatelský manuál stáhnout pdf (Strana 54)

50 Chapter 5 Documentation Number UD128A8D4602 Manual

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The GetSamples method requires one parameter, Count, that

specifies the maximum number of samples to return. The Get

Samples method returns data for all I/O points being sampled in a

two dimensional array. The index for the first dimension of the array

is the I/O point. The index for the second dimension of the array is

the sample number.

Dim SampleReadings() as Long

SampleReadings = Device1.GetSamples(5)

Now SampleReadings is an array that contains the next readings

after the previous GetSamples method. It will contain readings from

the I/O Points on Device1 that have their SamplingEnabled Property

set to True.

Note that the array may contain less than 5 samples if the device

has not completed 5 sampling periods since the last GetSamples

method call. The SampleRedings array is of the form

SampleReadings(I/O Point, Sample Number).

For example, if you enable sampling on AD0, AD2, AD3, and AD7

and request 5 samples at a time, then call the GetSamples method,

the returned array will look like this

Fig. 5.1 Timed Sample Array

(ch, sam) Samples Across

Ch Down #1 #2 #3 #4 #5

AD0 #1 V1,1 V1,2 V1,3 V1,4 V1,5

AD2 #2 V2,1 V2,2 V2,3 V2,4 V2,5

AD3 #3 V3,1 V3,2 V3,3 V3,4 V3,5

AD7 #4 V4,1 V4,2 V4,3 V4,4 V4,5

If there is an error during the one or more of the GetSamples values,

the value is flagged with the BDAQ_INVALID_DATA_VALUE instead

a value within the normal range below 4096. The most common

error is that it can't get the data from the driver and hardware fast

enough.

Your program needs to handle indicate where data is missing or

invalid and handle the holes.

For example, to display all the readings from AD7 in a text box called

txtAD7Result:

Dim i as Long

Dim SampleReadings() as Long

SampleReadings = Device1.GetSamples(100)

txtAD7Result = “”

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B&B Electronics 4 Channel Input Buffer Board SDAIBB Uživatelský manuál Strana 54