Burst Mode - Measurement Computing PCI-DAS1602/16 User Manual

PCI-DAS1602/16 User's Guide
Software selects the bipolar/unipolar input configuration and input range. The table below lists the analog input
ranges and resolutions for the available input configurations and gains.
Bipolar Range
±10 V
±5 V
±2.5 V
±1.25 V

Burst mode

Channel-to-channel skew results from multiplexing the A/D inputs. It is defined as the time between
consecutive samples. For example, if four channels are sampled at a rate of 1 kHz per channel, the channel
skew is 250 µs (1 ms/4).
Burst mode minimizes channel-to-channel skew by clocking the A/D at the maximum rate between successive
channels. Burst mode timing is illustrated in Figure 4. At the 1-ms pulse, channel 0 is sampled. After 5 µs,
channel 2 is sampled. Channel 3 is sampled 5 µs after channel 2 is sampled. No samples are then taken until the
next 1-ms pulse, when channel 0 is sampled again. In this mode, the rate for all channels is 1 kHz, but the
channel-to-channel skew (delay) is now 5 µs, or 20 µs total. The minimum burst mode skew/delay on the PCI-
DAS1602/16 is 5 µs.
CH0
5µS
The length of the delay between bursts is
set by one of the internal counters, or may
be controlled via the external trigger.
Input range and resolution
Resolution
305 µV
153 µV
76.3 µV
38.1 µV
CH1 CH2 CH3
Delay
Figure 4. Burst mode timing
Unipolar Range
0 to 10 V
0 to 5 V
0 to 2.5 V
0 to 1.25 V
CH0 CH1 CH2
Burst mode pacer is
fixed at 5.0 µS
16
Functional Details
Resolution
153 µV
76.3 µV
38.1 µV
19.1 µV
CH3