User`s guide

Operation Theory • 31
Scan with SSH
You can send the SSHOUT signal on CN2 to an external S&H circuits to
sample and hold all signals if you want to simultaneously sample all
channels in a scan, as illustrated in fig 11.
Note: The ‘SSHOUT’ signal is sent to external S&H circuits to hold the
analog signal. Users must implement external S&H circuits on their
own to carry out the S&H function. There are no on-board S&H
circuits.
4.1.4.2 Specifying Channels, Gains, and input configurations in the
Channel Gain Queue
Like software polling acquisition mode, the channel, gain, and input con-
figurations can be specified in the Channel Gain Queue under the scan
acquisition mode. Please refer to 4.1.3.1. Note that in scan acquisition
mode the number of entries in the Channel Gain Queue is normally
equivalent to the value of NumChan_counter (that is, the number of sam-
ples per scan).
Example:
Set
SI2_counter = 160
SI_counter = 640
PSC_counter = 3
NumChan_counter = 4
Timebase = Internal clock source
Channel entries in the Channel Gain Queue: ch1, ch2, ch0, ch2
Then
Acquisition sequence of channels: 1, 2, 0, 2, 1, 2, 0, 2, 1, 2, 0, 2
Sampling Interval = 160/40M s = 4 us
Scan Interval = 640/40M s = 16 us
Equivalent sampling rate of ch0, ch1: 62.5kHz
Equivalent sampling rate of ch2: 125kHz