MaxBurstRate

Applies to:

DATAQSDK Active X Control

Description:

The maximum burst rate determines how fast the board or hardware device samples all enabled channels combined (maximum sampling rate or maximum throughput rate). For example, if MaxBurstRate is set at 10,000 you could acquire 10 channels at a rate or 1,000 samples per channel per second. This property is independent of the SampleRate, which defines how fast sampled data is reported. However, SampleRate must be lower than MaxBurstRate.

Your hardware determines how fast you can sample data. Please consult your hardware manual to be absolutely certain you do not exceed hardware limitations. The default is the maximum throughput rate of the active Dataq hardware device (see DeviceDriver for an explanation of the active device). Programmers should be aware of what device they are creating a program for in order to avoid exceeding this limit.

When SampleRate and MaxBurstRate are set in your program, DataqSdk sets ADCounter and BurstCounter. If you set ADCounter and BurstCounter, it overwrites SampleRate based on the formula as displayed in BurstCounter. Use either SampleRate and MaxBurstRate OR, for devices other than the other than the DI-245, DI-1100, DI-1110, DI-1120, DI-2008, DI-2108, or DI-2108-P, ADCounter and BurstCounter.

Note: For DI-245, DI-1100, DI-1110, DI-1120, DI-2008, DI-2108, and DI-2108-P devices, MaxBurstRate should not be changed or examined before the ADChannelCount property is set and the ADChannelList method has been called.

Note: f more than one analog channel is enabled on the DI-245 or DI-2008, the maximum analog throughput per device is only one tenth of MaxBurstRate, and synchronized devices must have the same number of analog and digital channels enabled. The number of digital channels enabled does not affect the analog throughput, but each digital channel contributes as much as an analog channel to the total data throughput per device. If a no DI-2008 has more than one analog channel enabled, MaxBurstRate is the maximum sample rate per channel, and synchronized devices need not have the same number of channels enabled.

Note: MaxBurstRate for DI-2108-P devices is a total rate per synchronized device. The total maximum throughput is MaxBurstRate times the number of devices with channels enabled.

Note: For DI-149, DI-1100, DI-1110, DI-1120, and DI-2108 devices, MaxBurstRate is the maximum sample rate per channel instead of maximum total rate per device.

Syntax:      

DataqSdk1.MaxBurstRate=variable (where variable is a number between zero and the maximum sample rate of the hardware being used)

Variable:

Double

Example:

Private Sub DataqSdk1_ NewData(ByVal Count As Integer)

DQChart1. Chart (DataqSdk1. GetData)

End Sub

Private Sub Start_Click()

DataqSdk1. EventPoint = 20

'sample rate is set to 1000 - try to sample data at that rate

DataqSdk1. SampleRate = 1000

'200000 samples/second is the maximum sample rate for a DI-720 USB

DataqSdk1.MaxBurstRate = 200000

DataqSdk1. ADChannelCount = 2

DataqSdk1. Start

'actual sample rate would be about 1000

Label1.Caption = Format(DataqSdk1. SampleRate, "0.00")

End Sub

Private Sub Stop_Click()

DataqSdk1. Stop

End Sub