User Manual
AIC 324
1.2.2 Block Diagram
Figure 1
.2
– Module’s Block Diagram
The module includes the following functional blocks:
- Galvanically isolated digital and analog I/O unit.
- Digital I/O unit compatible with 8255.
- Timer unit compatible with 8254.
The analog I/O unit (XP9 connector) consists of a 16-bit ADC with a multiplexed 32x channel input, a
16-bit 4x channel DAC, a path calibration system, a temperature sensor and a digital input/output
channel. The multiplexed inputs of the ADC can be configured in 16 differential inputs or 32 non-
differential inputs. With the use of jumpers XP1 - XP8 in differential mode, the 0
– 15 differential
channels can be transferred to the current measurement mode by connecting current-measuring
resistors. The ADC can operate in unipolar and bipolar conversion modes. The path gain factor can
be changed from 0.5 to 8 with respect to the reference voltage of 5V. The calibration system makes it
possible to perform internal calibration of the board without the use of external means. The calibration
minimizes board measurement errors throughout the operating temperature range, and availability of
a thermal sensor allows you to save calibrations in nonvolatile memory for reuse when the board is
operating in the similar temperature modes. When performing calibration, it is not necessary to
disconnect the ADC input channels from the signal sources. When DAC calibration is performed, the
output channels must be disconnected, since the DAC generates voltages in the range of
± 10V at the
output. Calibration can be performed using the test program aictest (
“Aictest program. User Manual”)
or using functions from the function library supplied with the board (
“Functions Library: User Manual”).
Digital channels located in the galvanically isolated part of the board, have a fixed direction of
input/output and can be used both for the arrangement of synchronous operation of several boards
and for implementing digital I/O functions.
