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The heart of the 8400 System is the System Processor (SP), which links the host computer to the scanners and transducers. It provides calibration 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 systems. By adding additional components, the same 8400 can be expanded to more than 1000 channels for a powerful research and development system.
A new option for the 8400 configuration is the Scanner Digitizer Interface (SDI). The SDI configuration represents a major advancement in electronic pressure scanning technology that dramatically enhances data quality and increases productivity for windtunnel test applications. Existing conventional 8400 systems can be upgraded to the SDI configuration with the addition of new hardware and a firmware upgrade. Both conventional and DTC ESP scanners are supported by this new configuration.
8400 System Processor (SP)
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VME-Based for Simple Upgrades and Extended Lifespan
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High Speed IEEE-488 or Ethernet Interfaces
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Modular Configuration
Scanner Digitizer Unit (SDU) - Interfaces PSI's pressure scanners. Performs addressing 16 bit A/D conversion. Up to 50,000 samples/sec., 1024 channels max
Pressure Calibration Unit (PCU) - Programmable servo-controlled pressure calibrator with internal pressure measurement standard. Controlled from SP front panel or through interface. Available with differential or absolute pressure standards with long term accuracy of up to .01% Full Scale. Doubles as Pressure Standard Unit (PSU).
Calibration Pressure Range: 0-750 psia ±0.02% FS Accuracy
Pressure Standard Unit (PSU) - High accuracy pressure measurements. Quartz sensor for absolute measurement applications or HASS for differential. ±0.02% FS accuracy
For Measuring: Barometric Pressure, Total (Pt) and Static (Ps) Pressures, Scanner Reference Pressures
Interfacing & Expansion
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. An RS-485 multi-drop link is used to interface the SP to the RP. It provides eight additional input slots.
A Remote Slave may also be added. The Remote Slave is powered from the Remote Processor and communicates via the RS-485 link.
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 Remote Processor.
The user's choice of input units defines the system's overall operation. Various input units cover the following functions:
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Pressure Scanning
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Pressure Calibration
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Precision Pressure Measurement
System 8400 Specifications
| Maximum Pressure Inputs |
2,048 |
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Data Acquisition Rate |
200,000 MPS (4 SDUs) |
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Throughput |
50,000 MPS binary or 40,000 MPS E.U. |
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Interfaces |
IEEE-488 or Ethernet 802.3 |
Each unit is a self-contained module with a microprocessor-based controller board and a data acquisition or control personality card. When plugged into the SP chassis, all electrical/pneumatic signals are automatically connected.
On-Line Calibration
With internally controlled on-line calibration of Electronic Pressure Scanners, the 8400 system will maintain better than ±0.05% measurement uncertainty.
The PCU (Pressure Calibration Unit) has a microprocessor supervised servo-valve regulator as well as a high accuracy internal pressure standard which is used to accurately measure the pressure output. The 8400 is capable of simultaneously calibrating multiple pressure ranges using multiple PCUs.
 PSI Scanners & the 8400 System
The entire line of PSI pressure scanners interfaces to the 8400 SP through the Scanner Digitizer Unit
(SDU). Miniature ESP pressure scanners require the Model 84-IFC or S84-IFC interface.
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