Measurement Computing WBK30 - Manual (Page 4)

4 WBK30 User's Guide p/n 1025-0901 rev 2.0 (per EO# 2116R3)
"pace" the transfer by setting a transfer limit on the scan count. After the count reaches this value, the
driver stops transferring data. The transfer operation remains open and can resume when the application
sends a larger limit to the driver.
The pacing count is set by calling daqAdcTransferGetStat with the scan count argument initialized
to point to the pacing count and the active flag initialized to point to a value that is Boolean TRUE. The
pacing count can be called repeatedly during an acquisition to allow the driver to write more data. By
continually updating the pacing count as data is removed from the transfer buffer, the client can pace the
data transfer.
When not in Pacing Mode, daqAdcTransferSetBuffer behaves normally—the driver ignores
argument values. To get normal behavior while in Pacing Mode, initialize the active flag to point to a
Boolean FALSE. In all modes, the arguments always return scan count and status information regardless of
the active flag. Pacing Mode is enabled via daqAdcTransferSetBuffer by setting the
DatmPacingMode
bit of the transferMask argument.
WBK30 - Specifications
Name/Function: WaveBook Memory Option / expands internal data FIFO from 64 Ksamples to 8-64 Msamples
Memory Capacity (M = 1,000,000)
Part Number WBK30/16 WBK30/64 WBK30/128
Bytes 16.7 M 67.1 M 134.2 M
Samples 8.3 M 33.5 M 67.1 M
Packed Samples 11.1 M 44.7 M 89.4 M
Maximum Acquisition Length:
Pre-Trigger Acquisitions: Same as memory capacity
Post-Trigger Acquisitions: Depends on PC transfer rate, acquisition rate (both in samples per second), and capacity as follows:
Maximum Acquisition Length = T × acquisition rate Where: T = Time-to-overflow = Capacity / (acquisition rate - transfer rate)
Example: Acquiring 500 K unpacked samples per second with a WBK30/16 and a PC capable of transferring 200 Ksamples/second,
overflow will occur in: T = 8.3M / (500K - 200K) = 27.6 seconds
Thus: Acquisition Length = 27.6 seconds × 500K = 13.8 million samples
Pre-Trigger Mode: Allows indefinite pre-trigger duration, regardless of PC resources and transfer rate.
Environmental: 0°C to 70°C (compatible with WaveBook internal environment).
User Installation: Requires main board modification for Wavebook/512 shipped before July 1998. Plug-in compatible with
Wavebook/512 units shipped after July 1998 and all Wavebook/516s.
Mechanical Mounting: Friction fit with 40-pin header. Fit with foam rubber spacers in Wavebook/512; card guide in Wavebook/516.
Power: 300 mA maximum (200 mA typical) at 5 V
Dimensions: 2.6 x 4.1 inches.