User`s guide

34  Operation Theorem
Signal Channel
There are 16 channels in SE mode and 8 channels in DI mode. There are
two ways to control the channel number. The first is the software
programming and the second is the auto channel scanning, which is
controlled by the ASCAN bit in AD mode control register. As ASCAN is
cleared (0), the value of AD channel MUX register defines the channel to be
selected. Only one channel can be selected in one moment.
As ASCAN is set (1), the value in AD channel MUX register define the
ending channel number of auto-scanning operation. Under auto scan mode,
the channel is scanning from channel 0 to the ending channel. Whenever a
trigger signal is rising, the channel number to be selected will increase
automatically. For example, if the ending channel number is 3, the auto
channel scanning sequence is 0,1,2,3,0,1,2... , until the ASCAN bit to be
cleared.
The current A/D channel number could be read back from the A/D status
register. Refer to section 4.8 for the register format of the A/D status register.
Signal Range
The proper signal range is important for data acquisition. The input signal
may be saturated if the A/D gain is too large. The resolution of data may be
not enough if the signal is small and gain is not enough. The maximum A/D
signal range of ACL-8316 is +/- 10 volts when the A/D gain value is 1. The
A/D gain control register controls the maximum signal input range. The
signal gain is programmable with 4 levels (1,2,4,8). The signal range of the
16 channels will be identity all the time even if the channel number is
scanning.
The available signal polarity on ACL-8316 is only bipolar but no unipolar
configuration. However, the bipolar input range still covers the unipolar
applications. Therefore, ACL-8316 is suitable for full range of applications.