VisSim Real-Time
The Windows Solution for
Hardware-in-the-Loop Systems
The
VisSim/Real-Time add-on provides the ability to connect a VisSim
system model directly to the external world through digital and
analog I/O. With VisSim/Real-Time, hardware-in-the-loop systems can
be performed by interfacing VisSim plant or controller models to
real-world hardware. VisSim/Real-Time supports computer I/O boards
from
Measurement Systems,
National Instruments, Advantech, and ACS
Tech80 high-speed motion control interface cards. No code generation
or programming is required to configure VisSim/Real-Time.
VisSim/Real-Time is used successfully in a
wide variety of industries to :
With VisSim/Real-Time, engineers can perform
real-time simulation, data acquisition and control directly from
Windows 9x/NT. There is no code generation or programming involved,
and there is virtually no difference between running a regular
VisSim simulation and a real-time HIL system.
Configuring a Hardware-in-the-loop System
Connecting VisSim to the real world is
simple:
-
Select the I/O card(s) from the list of
supported boards
-
Install the I/O card(s)
-
Place realTime dataIn and dataOut
blocks into the VisSim diagram for each I/O channel to be
accessed.
-
Right click each realTime block to
configure as digital, counter, volts, 4-20 ma, or
thermocouple in the dialog box
-
Select "run in real-time" in the
simulation properties dialog -
Click "Go" to start reading and writing the I/O
channels
Controller
Validation
VisSim/Real-Time lets you execute your
VisSim based control algorithm to control a physical plant in
real-time up to 20 kHz sampling rates. This lets you rapidly
prototype different control strategies.
Off-Line Tuning and Monitoring
Off-line tuning of controllers is done by
developing a plant model that runs in real-time. Then plant I/Os are
connected to the control hardware via VisSim/Real-Time to fool the
controller under test to thinking it is connected to a real plant.
By leveraging VisSim's fast execution speed, this is an excellent
way to check out controller performance against an accurate plant
model.
When the control validation is complete, the
control hardware is disconnected from the plant model and connected
directly to the real plant. This process ensures faster, safer and
less costly system and equipment ramp-ups. Off-line tuning is
especially useful in the process control industries as it enables
validation of controller design without any equipment shut down. It
is an important technique for use with sensitive equipment where a
poorly designed or untested controller could result in costly damage
to the equipment.
VisSim/Real-Time at GE Motor & Drive Division
The Motor and Drive Systems Division of
General Electric (GEMIS), based out of Salem, Virginia, is one of
the largest manufacturers of electrical drive systems worldwide.
Using VisSim and VisSim/Real-Time, engineers recently completed
prototyping a Resonance Eliminator Controller (REC) for industrial
drive systems used in metals rolling applications. The goal of the
controller, according to Emil Kuelz and Sandy Gurian, System
Engineers for GEMIS, is to reduce resonance vibrations in the shafts
and rolls of the mechanical system. Kuelz and Gurian modeled the
motor and mechanical system in VisSim, and then incorporated the
REC. The REC computes a motor torque correction signal from shaft
torque measurement, which in turn is applied to the mechanical
system at a specific resonant frequency.
To test the design, Kuelz and Gurian used
two PCs, each running VisSim/Real-Time. One PC contained the motor
and mechanical system simulation; the other, the REC. VisSim's
A-D/D-A real-time interface allowed the two models to exchange
information. This configuration verified that controller performance
would not be degraded by either time delays introduced by the
A-D/D-A conversions or the precision of the 12-bit DAC. "The
simulation results assured us that the REC would function properly
when attached to the actual motor and mechanical system," said
Kuelz.
After verification, Kuelz and Gurian
disconnected the PC with the REC from the PC with the motor and
mechanical system simulation, and reconnected it to the real motor
and mechanical system in GEMIS's in-house laboratory. The first time
the REC was turned ON, it totally eliminated the mechanical system
resonance.
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VisSim model of GE industrial drive system with
Resonance Eliminator Controller. Upper plot shows amount of
correction applied to motor torque. Lower plot shows drive
speed. |
Real-Time I/O cards & data channels can be
configured directly from VisSim via intuitive dialog boxes.
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By developing and testing the REC in VisSim
and VisSim/Real-Time, Kuelz and Gurian focused exclusively on
proving the viability of the design. "The risks of connecting an
unproved design to a large horse power electrical drive and
mechanical system are great," said Kuelz. "If incorrectly designed
and not thoroughly tested, it can cause motor, shaft, and coupling
failure, resulting in a process outage costing millions of dollars."
VisSim/Real-Time for Process Control
Applications
HIL simulation is a critical requirement for
the chemical, petrochemical, power, paper & pulp, pharamceutical
and food process industries. The cost of inefficient control
strategies or poor product/ controller transitions is enormous.
Companies, like DuPont (Non-Woven and AFS Spruance facility,
Richmond, VA) are successfully using VisSim/Real-Time to validate,
tune and monitor their process control equipment. For more details,
request the DuPont case study.
CLICK HERE FOR
VISSIM/REAL-TIME BOARD SUPPORT LIST
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