User`s guide

Operation Theory

29
Figure 11: Scan Timing
There are 4 trigger modes to start the scan acquisition, please refer to
4.1.3.3 for the details. The data transfer mode is discussed in 4.1.3.4.
Note:
1. The maximum A/D sampling rate is 250kHz. Therefore, the minimum
setting for SI2_counter is 160 while using the internal Timebase.
2. The SI_counter is a 24-bit counter and the SI2_counter is a 16-bit
counter. Therefore, the maximum scan interval using the internal
Timebase = 2
24
/40Ms = 0.419s, and the maximum sampling interval
between 2 channels using the internal Timebase = 2
16
/40Ms =
1.638ms.
3. The scan interval can’t be smaller than the product of the data sam-
pling interval and the NumChan_counter value. The relationship can
be represented as: SI_counter>=SI2_counter * NumChan_counter.
A
cquisition_in_progress
Scan_start
A
D_conversion
Scan_in_progress
(
SSHOUT
)(
pin8 on CN2
)
3 Scans, 4 Samples per scan
(PSC_Counter=3, NumChan_Counter=4)
Sampling Interval t=
SI2_COUNTER/TimeBase
Scan Interval T=
SI_COUNTER/TimeBase
Ch2
Ch3
Ch1
Ch0
Ch2
Ch3
Ch1
Ch0
Ch2
Ch3
Ch1
Ch0
( channel sequences are specified in Channel Gain Queue)