Rs
50
1k
10k
+Vcc
-Vcc
+Vcc
-Vcc
Vo
-
-
+
-
+
Is
Fig.6 the OP amplifier circuit for Hall sensor
(c)Temperature Measurement
The working temperature of DC motor is measured
by HIOKI3444. HIOKI3444 is an accurate temperature
non-contact meter. The measured temperature data is
sent to DAQ card through analog output cable. The
measured data is recorded and displayed on monitor by
LabVIEW. The structure of temperature acquisition is
shown in Fig. 7.
Fig.7 The structure of temperature acquisition
(d)Data Acquisition system
DAQ (Data Acquisition) system digitizes the analog
measured data simultaneously for DC motor. The
digitized data is recorded and analyzed further by using
LabVIEW. The command also is sent to relay switch
through DAQ output port. The relay switch is
controlled and operates properly. Fig. 8 shows a
connected circuit between DAQ input/output port and
current sensing circuit.
Fig.8 the Actual Electric Circuit Wiring Diagram of
Hall Component DAQ Card Output the PORT
2.3 Software System
LabVIEW is a graphical programming language
from National Instruments. It is easier than traditional
programming language. LabVIEW is based on that
data flows composes program [5-7]. The decision of
operation order and interaction of data flow are
important issues. The powerful functions, including
friendly human-machine interface, good mathematical
operation and excellent support of instruments are very
useful to set up automatic measurement and
examination platform. Therefore, rapid development
and accurate experimental results can be reached.
LabVIEW program structure is also called Virtual
Instruments (VI). A standard VI contains three parts
described as follows:
z
Front Panel
The front panel is regarded as control panel of true
instrument. It provides many options for Control and
Indicator objects, for instances, pressed key, knob,
switch, graph, and other numerous output/input
components. When a value is set to input Control, the
corresponding output results can be observed from
programming block diagram.
z
Programming Block Diagram
Every front panel is corresponded with a
programming block diagram, called VI program. The
element of programming block diagram is icon. The
connected line between icons links the data
communication.
z
Icon and Connector
When VI is set as sub VI it needs a connector to
transmit data for icon. The right upper corner of virtual
instrument window shows an editable icon. The
connector is the interface between the corresponding
virtual instrument and outside. Each rectangle of the
block represents a terminal respectively. It can
represent an input or output terminal of corresponding
virtual instrument.
According to above discussion, the software system
of automatic measurement and examination platform is
set up and described in following sections.
(a)Data Acquisition
DAQ system digitizes the analog measured data for
DC motor. A series of DC motors can be examined
through A/D channels simultaneously. The proper
sampling mode, sampling rate and etc, is assigned by
VI block diagram. In this paper, important parameters,
including transient current, steady current and motor
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