Functions > di_maximum_rate

Syntax 

The di_maximum_rate function sets the maximum Burst Rate for the device.

Syntax 

double di_maximum_rate(double max_burst_rate);

Parameters

The default maximum burst rate is the maximum burst rate allowed for the device.

Return Value

Returns the maximum burst rate for the device that is closest to the requested value within the capability of the device. For some devices this is independent of the parameter.

Dependencies

di_sample_rate

Remarks

This function should be called to avoid exceeding bandwidth capabilities of DI-720, DI-722, DI-730, and DI-78x products. The default setting for all DI-720, DI-722, DI-730, and DI-78x instruments is 250,000 (check your hardware documentation for sample rate specifications). For example, the maximum sample rate for a DI-722 is 50,000. To avoid exceeding bandwidth capabilities, max_burst_rate should be set to 50,000 or lower.

Note: The Minimum value for Maximum Sample Rate should not be confused with the minimum value for di_sample_rate, which is typically smaller by a factor of 32767.

 

Instrument Maximum Sample Rate (default) Recommended Maximum Sample Rate Minimum Value for Maximum Sample Rate
DI-145, DI-154, DI-195B, DI-194 Baud Rate/201 Baud Rate/201 Baud Rate/201
DI-148, DI-158 14400 14400 450
DI-1492, DI-155 10000 10000 11.44427
DI-245 2000 2000 64.5161
DI-220, DI-221TC,
DI-222 (Rev A or B)		 50000 50000 500
DI-222(Rev C or later) 80000 80000 732.45
DI-1100 1600006 200006 10000
USB DI-1110, DI-1120, DI-2108, DI-4108, DI-4208, DI-4718B, DI-4730 1600003 200003 100003
Ethernet DI-4108, DI-4208, DI-4718B, DI-4730 1000003 125003 62503
DI-2008 20004 20004 64.51614
DI-2108-P 1600004 400004 200004
DI-400, DI-401 500000 250000 500
DI-410 500000 100000 500
DI-700 976.5625 or 488.281255 976.5625 or 488.281255 976.5625 or 488.281255
DI-71x 4800 4800 112.5
DI-500, DI-510, DI-5001, DI-720, DI-722, DI-730, DI-740
Printer Port Devices in Standard Mode		 200000 40000 500
DI-500, DI-510, DI-5001, DI-720, DI-730
Printer Port Devices in Bi-directional Mode		 200000 80000 500
DI-500, DI-510, DI-5001, DI-720
Printer Port Devices in EPP Mode		 200000 200000 500
DI-730
Printer Port Devices in EPP Mode		 200000 150000 500
DI-500, DI-510, DI-5001, DI-720
USB Devices		 200000 150000 500
DI-500, DI-510, DI-5001, DI-720
Ethernet Devices		 200000 180000 500
DI-722, DI-740
(all devices EXCEPT printer port devices in Standard mode)		 200000 50000 500
DI-730
USB and Ethernet Devices		 200000 150000 500

1 See Baud Rates.

2 DI-149 limits apply to the total sample rate, but arguments and return values for di_maximum_rate and di_sample_rate are per channel values. With arguments of 1000 to both functions, all eleven channels may be enabled for a total throughput of 11000.

3 These values are maximum per channel and when multiplied by the numbers of channel enabled, the result should not exceed 160000. Call di_inlist, di_maximum_rate, and di_sample_rate in that order.

4 Call di_inlist, di_maximum_rate, and di_sample_rate in that order. For synchronized DI-2008 or DI-2108-P devices, this sets the maximum throughput per device.

5 488.28125 under Windows XP or Vista.

6 These values are maximum per channel, and when multiplied by (number of channels enabled plus 2) the result should not exceed 120000.

di_maximum_rate can also be used to achieve sample rates lower than the maximum sample rate for the device divided by 32767 and to reduce cross-talk into channels driven by high-impedance sources. Although the Maximum Sample Rate for the device is the default when using DataqSdk.ocx, the SDK DLL user must call di_burst_rate or rely on di_sample_rate to do it indirectly before starting a scan.

If di_open has not been called successfully or if the device has been closed, the return value for di_maximum_rate is 0.0.

DI-1100, DI-1110, DI-1120, DI-2108, DI-4108, DI-4208 arguments and return values for sample rate are per channel values. Both di_list_length and di_inlist must be called first. Call di_maximum_rate first, and di_inlist again after di_sample_rate to set the counter values.

Sample Code

error_code = di_open(1);

/* for a device on parallel port LPT1 */

actual_max_rate = di_maximum_rate(50000.0)

/* for a DI-722 */

 

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