User`s guide

16 • Operation Theorem
Signal Channel Control
The value of AD channel Control register defines the channel to be selected.
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. Sometimes, the resolution may
be not enough if the signal is small. The maximum A/D signal range of ACL-
8113A 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 5 levels (1,2,4,8,16). The signal range of the 32 channels
will be identical. The available signal polarities on ACL-8113A could be bi-
polar and uni-polar configuration.
4.3 A/D Trigger Source Control
The A/D conversion is started by a AD conversion trigger source, and then
the A/D converter will start to convert the signal to a digital value. In ACL-
8113A, the only trigger source is software trigger. That is, the A/D conversion
is starting when any value is written into the software trigger register. This
trigger mode is suitable for low speed A/D conversion. Under this mode, the
timing of the A/D conversion is fully controlled by software. However, it is
difficult to control the fixed A/D conversion rate unless another timer interrupt
service routine is used to generate a fixed rate trigger.