User`s guide

Universal Library User's Guide Analog Input Boards - PCI-2500 Series

DAQ output (PCI-2517 and PCI-2515 only)

DAQ output functions and methods supported

UL: cbDaqOutScan()

UL for .NET: DaqOutScan()

DAQ output argument values

Options BACKGROUND, CONTINUOUS, EXTCLOCK, SIMULTANEOUS, NONSTREAMEDIO,

ADCCLOCKTRIG, ADCCLOCK

ChanType ANALOG, DIGITAL16

ChanArray ANALOG: PCI-2517: 0 to 3

PCI-2515: 0 to 1

DIGITAL16: FIRSTPORTA (FIRSTPORTB must be configured as an output)

Rate ANALOG: Up to 1 MHz

DIGITAL16: Up to 12 MHz if no analog channel is selected.

Otherwise up to 1 MHz.

Range Ignored

Hardware considerations

Channel count

For input and output scans, the count must be set to an integer multiple of the number of channels or a

BADCOUNT error is returned.

Sampling and update rates

Sampling and update rates are system-dependent. Data overruns/underruns may occur with higher sampling

rates when using BACKGROUND and CONTINUOUS modes. To avoid this, use a larger buffer/count size, or use

NONSTREAMEDIO mode, if supported. The minimum size buffer is 256 for cbAOutScan(). Values less than that

result in a BADBUFFERSIZE error.

Settling time

For most applications, settling time should be left at the default value of 1 µs. However, if you are scanning

multiple channels and one or more channels are connected to a high impedance source, you may get better

results by increasing the settling time. Keep in mind that increasing the settling time reduces the maximum

acquisition rate. You can set the time between A/D conversions with the ADC Settling Time option in

InstaCal. Select between 1 µs, 5 µs, 10 µs, or 1 ms.

Setpoints

You enable setpoints with the SETPOINT_ENABLE flag. This flag must be OR'ed with the ChanTypeArray

argument values. You set the setpoint criteria with the cbDaqSetSetpoints()/DaqSetSetpoints(). The

number of channels set with the SETPOINT_ENABLE flag must match the number of setpoints set by the

SetpointCount argument (cbDaqSetSetpoints()/DaqSetSetpoints()).

Output non-streamed data to a DAC output channel

With NONSTREAMEDIO mode, you can output non-streamed data to a specific DAC output channel. The

aggregate size of the data output buffer must be less than or equal to the size of the internal data output FIFO

in the device. The FIFO holds 524288 samples. This allows the data output buffer to be loaded into the

device‘s internal output FIFO. Once the sample data are transferred or downloaded to the device, the device is

responsible for outputting the data. You can't make any changes to the output buffer once the output begins.