Another synchronous mode allows digital inputs to be scanned every time an analog input channel is
scanned. For example, if eight analog inputs are scanned at 1 µsec per channel continuously, and 24 bits of
digital inputs are enabled, then the 24 bits of digital inputs will be scanned at 24 bits per 1 µsec. If counters
are enabled in this mode, they will be scanned at once per scan, in the same manner as in the first example
above.
Note
: It is not necessary to read counters as often as it is to read digital inputs. This is because counters
continue to count pulses regardless of whether or not they are being read by the PC.
Example 1: Analog channel scanning of voltage inputs
The figure below shows a simple acquisition. The scan is programmed pre-acquisition and is made up of 6
analog channels (Ch0, Ch2, Ch5, Ch11, Ch22, Ch25.) Each of these analog channels can have a different
gain. The acquisition is triggered and the samples stream to the PC via DMA. Each analog channel
requires one microsecond of scan time therefore the scan period can be no shorter than 6 us for this
example. The scan period can be made much longer than 6 us, up to 19 hours. The maximum scan
frequency is one divided by 6us or 166,666 Hz.
Notice that some of the analog channels in the scan group are from a PDQ30 expansion module. All
analog channels are sampled at the same rate of 1us. Analog channels on the PDQ30 can also have any of
the gain ranges applied.
DaqBoard/3000 Series User’s Manual
988093
Daq Systems and Device Overviews 1-5
Summary of Contents for OMB-DAQBOARD-3000 Series
Page 7: ...This product requires one of the following Operating Systems Windows 2000 Windows XP ...
Page 14: ...IG 8 DaqBoard Installation Guide 918494 1033 0940 rev 8 0 ...
Page 36: ...2 8 Connections Pinouts 918494 DaqBoard 3000 Series User s Manual ...
Page 40: ...4 2 Calibration 918494 DaqBoard 3000 Series User s Manual ...
Page 80: ...6 12 Setpoint Configuration for Output Control 908794 DaqBoard 3000 Series User s Manual ...
Page 102: ...DBK215 pg A 14 948894 Appendix A ...
Page 104: ...B 2 Hardware Analog Level Trigger 90794 Appendix B ...