Real-time Mach Reporting and Control Tied to Your Wind Tunnel Data
Mach Accuracy to ±0.001
System
8400 SP Data Acquisition
With
hundreds of systems in use worldwide, the 8400 is the standard for wind
tunnel and turbine pressure measurement. It's a modular, parallel processing
system for high speed pressure and frequency scanning up to 200,000 measurements
per second. Its measurement range is from 10 inH2O to 750 psi.
The heart of the system is the System Processor (SP), which links the host
computer to the scanners and transducers. It provides input unit control,
data synchronization, conversion of raw data to engineering units and an
IEEE-488 interface (or Ethernet) to the host computer.
The modular design of the 8400 permits users to configure small product
test systems. By adding additional components, the same 8400 can he expanded
to more than 1000 channels for a powerful research and development system
.
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2
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PRESSURE
CALIBRATE UNIT
Programmable servo-controlled pressure controller with internal pressure
measurement standard. Controlled from SP front panel or through interface
PRESSURE
STANDARD UNIT
High accuracy pressure measurements. Quartz sensor for absolute measurements
applications or HASS for differential. ±0.02% FS accuracy.
PRESSURE
INPUT UNIT
4,8, or 16 channels of pneumatic pressure measurements. Digital compensation
and re-zero. ±0.15% FS accuracy (with PCU ±0.05%). Option
for 256 channels or 16 liquid channels.
PRESSURE
BLANKING UNIT
For unused input unit slots.
FREQUENCY
MEASUREMENT UNIT
4 channels of frequency and period measurements. From 0.1 to 100 KHz
Accepts TTL, optically coupled, and low level AC coupled inputs.
SCANNER
DIGITIZER UNIT
Interfaces PSI’s pressure scanners. Performs addressing &
14 or 16 bit A/D conversion. Up to 50,000 samples / sec., 1024 inputs.
INPUT
DEVICES / SIGNALS
Barometric
Pressure, Pt, Ps.
Non atmospheric Reference Pressure.
Nozzle Inlet Pressure.
Pressure
Transducers.
LVDTs.
Speed
Sensors.
Tachometers.
Pulse Output Sensors.
Input
Units
The
SP chassis can house up to eight input units. Applications needing more
units can be accommodated with the addition of a local slave or self powered
remote processor.
The users choice of input units defines the systems overall operation. Five
different input units cover the following functions:
Pressure Scanning
Pressure Calibration
Precision Pressure Measurement
Frequency Measurement
Each unit is a self contained module with a microprocessor based controller
board and a data acquisition characterised card. When plugged into the SP
chassis, all electrical/pneumatic signals are automatically connected. Up
to 64 input units may be used.
On-Line
Calibration
With
internal on-line calibration, the 8400 system will maintain ±0.05%
measurement uncertainty.
The PCU (Pressure Calibration Unit) has a servo-controlled output pressure
regulator and an internal pressure standard with ±0.02% accuracy. All
ranges calibrate simultaneously with multiple PCUs.
For applications requiring more than the eight input
slots available in the system processor, a Local Slave (LS) chassis
may be interfaced to the SP via an IEEE-488 interface. For applications
requiring the pressure calibration units to be remotely located near
the test article, a Remote Processor (RP) can be used. The remote
processor is a self-powered unit which may be located up to 1000 ft
away from the SP and interfaced via an RS-485 multi-drop link It provides
eight additional input slots.
A remote slave may also be added The remote slave is powered from
the remote processor and communicates back to the SP via the RS-485
link.
All of PSI pressure scanners interface to the 8400 SP through the
Scanner Digitiser Unit (SDU). Miniature ESP pressure scanners
require
the Model 84 IFC or S84 IFC interface. Rack pressure scanners require
an S3200 RK or S1600HD RK interface rack. Both rack-mount and
miniature
ESP scanners may be configured in the same system.
Typical
Configurations
The
following are examples of high speed wind tunnel/turbine pressure scanning
split over 3-7 pressure ranges.
Example 1
Example 2
Example 1: Turbine Test
In this example, two sets of HD scanner racks, each with eight scanners,
provide for a large number of channels (256), a high scan rate (50,000
per sec), and multiple pressure ranges. The LS is used to support
additional PCUs.
Example 2: Wind Tunnel
Wind tunnels use miniature ESP scanners inside the test model with
PCUs nearby to minimize pneumatic lengths to decrease pressure settling
time. An S84 IFC/SJU interfaces the ESPs to the SDU. Pneumatics are
not needed in the SP
The 8400 Flow Reference System (FRS)
is a self-contained multiple range pressure measurement system for
measurement of wind tunnel static (Ps) and total (Pt) pressure.
From the precise measurement of Pt and Ps, users can derive dynamic
pressure, flow velocity, Reynolds number and Mach. The inherent accuracy
and auto ranging capability of the FRS provide the ability to derive
the Mach number to an accuracy of +0.001.
The 8400 FRS is contained in a 19" rackmountable chassis, rugged
enough to be placed near the tunnel on the centre line to reduce pneumatic
hydrostatic effects. It consists of a modified 8400 SP with up to
4 built-in Pressure Standard Units (PSU) of different ranges, covering
the entire operational envelope of Pt and Ps.
The FRS selects the most sensitive PSU ranges to optimise accuracy
during operation. An optional precision temperature measurement
sub-system
allows for the measurement of tunnel total temperature. The FRS operates
in a triggered mode up to 10 readings per second and is provided
with
dual redundant IEEE-488 interfaces for measurement and control applications.
An optional Ethernet IEEE-802.3 interface is available for networked
systems.
