User`s guide

Operation Theorem  31
4.1.1 A/D Conversion Procedure
For using the A/D converter, users must know about the property of the signal
to be measured at first. The users can decide which channels to be used and
connect the signals to the ACL-8316. Refer to the ‘Signal Connection’
(Section 2.11). In addition, users should define and control the A/D signal
sources, including the A/D channel, A/D gain, and A/D signal types. Please
refer to section 4.1.2. for A/D signal source control.
After deciding the A/D signal source, the user must decides how to trigger the
A/D conversion and define / control the trigger source. The A/D converter will
start to convert the signal to a digital value when a trigger signal is rising. The
ACL-8316 provides three trigger modes, refer to section 4.1.3 for details.
At the ending of A/D conversion, the A/D data is stored in A/D data register
and in the FIFO if FIFO is enable. This issue stands as A/D data buffering.
Please refer to section 4.1.4.
The A/D data should be transferred into PC's memory for further using or
processing. The data can be either read by I/O instruction which is handled
directly by software or transferred to memory by the DMA controller. Please
refer to section 4.1.5 to obtain ideas about the multi-configurations for A/D
data transferring.
To process A/D data, programmer should know about the A/D data format.
Refer to section 4.1.6 for details.
4.1.2 A/D Signal Source Control
To control the A/D signal source, three concepts should be understood. That
is signal type, signal channel and signal range.
Signal Type
The A/D signal sources of ACL-8316 could be single ended (SE) or
differential input (DI) type. The signal type is selected by external jumper
(JP7). The setting can be read back through the D/A format register.
ACL-8316/12 provides 16 single-ended or 8 differential analog input channels.
The analog signal can be converted to digital value by the A/D converter. To
avoid ground loops and get more accuracy measurement of A/D conversion,
it is quite important to understand the signal source type and how to choose
the analog input modes: signal-ended and differential. The ACL-8316/12
offers jumpers to select 16 single-ended or 8 different analog inputs.
Single-ended Mode:
The single-ended mode has only one input relative to ground and it suitable
for connecting with the
floating signal source. The floating source means it
does not have any connection to ground. The following figure shows the