Scireq flexivent, User Manual, Page: 17 / 86

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contained in every UNIT scales and linearizes the signals and performs self-tests and local
control functions. The controller also retains calibration and identification details that are
communicated digitally to the instrument and the host software to log the system configuration
and assert its integrity.
A common example for a simple UNIT is shown in UNIT A in Figure 1-2. This UNIT has a single
analog input channel to measure a signal from a single sensing element and communicate it to
the instrument and the software. A precision differential pressure transducer such as model
UT-DPD-02 is an example of this type of UNIT.
UNIT B in Figure 1-2 provides an example of local low-level servo control. This UNIT combines an
analog input channel with an embedded actuator that has the ability to manipulate the attribute
being measured in order to simultaneously collect the actual measurement and push it towards
a desired value as provided by the instrument and/or the software. An example for this type of
UNIT would be a temperature-controlled water bath.
UNIT C in Figure 1-2 provides a further example of the platform’s flexibility as it shows 3 analog
input channels communicating measurements to the software while a fourth digital output
channel is used to allow the software to switch or send synchronization signals to outside
instruments.
1.2.4 INTEGRATED SYSTEMS
In
UnitWise
terminology, some SCIREQ products are referred to as “integrated systems” since
they contain both an instrument and one or more UNITs in a common package. For example, a
flexiVent
FX has all features of a
UnitWise
instrument (Ethernet, ports and embedded display)
but also possesses several internal ports to measure and control volume displacement,
pressures and valve states. Integrated systems such as the
flexiVent typically feature a limited
number of external (auxiliary) ports for accessories, and their port count can be further
extended by adding a secondary instrument (see section
1.2.2).
Some integrated systems offer functionality that goes above and beyond the capabilities of a
standard
UnitWise data acquisition system (e.g. mechanical ventilation for the flexiVent , pump
profiles for the
inExpose
). When working with an integrated system such as the
inExpose
or the