manufacturer: Foss
model: NIR-System
annotation: Dokumente engl.
Instrument Overview
The NIRSystems holographic grating series of monochromators are designed to provide unprecedented reliability, sensitivity, and ruggedness during Operation. Using the best technology available, the instrument family allows for superior reliability and long term stability.
These instruments provide extraordinary sampling flexibility through use of interchangeable sampling and detector modules. NIRSystems currently offers over 20 different sampling and fiber optic systems for the holographic grating series of instruments.
Sampling modules are designed to simplify and integrate sample presentation to the instrument. Since materials vary tremendously in their shape, consistency, and handling characteristics, several different sampling modules can be used on a single system. Nearly all types of sample forms, from liquids to slurries and solids, from single tablets to finely ground powders or coarse materials can be analyzed.
Monochromator Chassis
The basic monochromator chassis Supports and maintains alignment of all holographic grating instrument components. This chassis contains the AC Input, fuse, power supply, optics plate, and pre-heater to reduce instrument warm-up time. All major instrument components (described below) are mounted to the instrument chassis.
Laboratory sampling modules and detectors attach to the instrument through
a universal adapter plate. Power for all detectors and modules is supplied through a D-connector on the universal adapter plate. Signals from the monochromator are passed back and forth through the saure connector. Optical alignment is automatic.
Instead of sampling modules, process instruments use fiber optic light guides to route NIR energy in and out of the sealed NEMA 4 enclosure. Process instruments share all major instrument components with the laboratory systems.
Power Supply
All NIRSystems instruments operate from a universal power supply, which accepts voltages and frequencies from around the world, from 100VAC to 240VAC, either 50 or 60 Hz. This power supply gives excellent damping of electrical transients and noise, and provides a clean stable voltage to the instrument electronics.
The power supply output is 14 and 15 volts DC for the laboratory and process instruments respectively. Total power consumption of the instrument is 200 watts or less, depending upon modules. Note: Clean filtered power is recommended.
Grating Drive Assembly
Both laboratory and process instruments share a common grating drive assembly, which is the heart of the instrument. This optical System provides both the precision and rugged construction required for reliable analysis.
A concave holographic grating, ruled with fine lines to separate light into individual wavelengths, is mounted directly to the shaft of a precisely-controlled positioning motor. A high-resolution encoder is coupled to the same shaft to complete the assembly. The encoder reports the rotational position (of the grating) to the circuitry which correlates rotational position with wavelength position.
This assembly, combined with patented internal reference Standards, assures longiere wavelength accuracy and precision. All of the optical components are enclosed in sealed chambers to minimize environmental effects upon the instrument. Note: Operating Range 60° to 90°F (25° to 32°C) with no environmental protection.
Source Lamp And Lamp Regulator
The energy source is a tungsten-halogen filament lamp with a customized reflector. NIRSystems takes several patented steps to insure reliable performance and easy calibration transfer, including a high efficiency metallic coating on the lamp reflector, control of the lamp energy output, initial burn-in, and filament pre-alignment.
A lamp voltage-regulating circuit precisely controls the source energy to improve measurement stability. The lamp is aligned in a mounting fixture which is installed in the monochromator with a single knurled thumbscrew and two wires to the terminal block on the lamp regulator board.
Order Sorter Filter
White light striking a diffraction grating separates into mang orders of radiation, each comprising a spectrum dispersed across a certain angle. A characteristic of this diffraction is the partial overlap of orders.
As a result, different wavelengths originating from different orders occur in the same position. For example, the wavelengths 2400 nm, 1200 nm, and 800 nm from the 1 st, 2nd, and 3rd orders, respectively, might be superimposed.
Preferably, only first order radiation is used for spectrophotometry, as it is most intense. Radiation from other orders raust be blocked from the exit slit to prevent "contaminating" the first order radiation used for spectral analysis. This is accomplished with order sorter filters, a Set of high-pass filters with different skort wavelength cutoffs. Mounted in a paddle whose position is precisely controlled by a Stepper motor, the filters are cycled through the beam in concert with grating rotation. This patented technique makes purely first order radiation available from 400 nm to 2500 nm in a single scan.
Internal Wavelength Linearization Standards
Internal wavelength standardization provides long-term wavelength accuracy and precision for all NIRSystems instruments. Wavelength calibration is performed by measuring internal standards and analyzing their peak positions versus reference positions.
Since they have well-defined absorptions in appropriate spectral regions, a polystyrene standard (4 peaks) is used in the 11002500 nm region, and a polystyrenedidymium standard (3 peaks) is used in the 400-1100 nm region.
Actual peak positions are compared with reference peak positions stored in a Software table. Differences between reference and actual peak positions are calculated, and corrections are made by the instrument Software which are applied to all subsequent sample spectra. This procedure can be performed automatically whenever a reference is scanned, as well as part of regular diagnostics.
Instrument Detectors
The monochromator raust be configured with at least one detector for testing and sampling. The traditional detector types are reflectance for collecting diffusely scattered radiation from a sample surface and transmission to collect the radiation transmitted through a sample.
Fiber optic sampling offers flexibility for both laboratory and process instruments. Depending an the probe and fiber optic Systems, a reflectance or transmission detector is used to measure the collected radiation.
Reflectance detectors are designed to gather energy reflected off the sample with minimal effect from specular reflection.
Detector elements are mounted at a 45- degree angle to the sample surface receiving 0° Illumination, to eliminate specular reflectance off the window material. Reflectance measurements involve the collection of the diffusely scattered radiation from the sample.
Multiple detectors are used to increase the collection area and signal detection. A typical reflectance detector assembly contains 4 Lead Sulfide detectors (11002500 nm) and 2 Silicon detectors (4001100 nm).
Transmission detectors contain one lead Sulfide and one Silicon detector which are mounted directly where the beam exits the sample material, for maximum energy detection.
NIRSystems instruments use a unique System of gain optimization called "AutoGain", which uses the first scan of each data collection to adjust the gain level for the best resolution of signal.
The instrument picks a gain factor to prevent either a low or high (saturated) signal. The gain factor depends upon the sample absorbance, requiring no user adjustment. Similarly, detector block temperature is tightly controlled during instrument Operation to maximize stability.
Optional:
Vision I/0 Module
Features and Benefits
- Self-contained design including on-board power supply for analog and digital devices.
- 24 Digital input/output devices with up to 24 Analog outputs.
- Compact design to fit into existing industrial equipment rack.
The Foss Nirs-Systems Vision I/O Module provides a user-friendly means of controlling a process in conjunction with a Foss NIR-Systems Process Analytics Spectrometer via 4-20 mA analog outputs. The I/O Module is designed to operate with the new windows based Vision software. Configuration of the I/O devices is easy in the windows environment. The I/O Module is supplied standard with 9 Digital Inputs, 15 Digital Outputs and either 8, 16 or 24 Analog outputs.
Typical Digital Input Signals include:
- System Ready Indicator
- Product Select (up to 32 products)
- Multiplexer Channel Select (up to 9 channels)
- Run Analyzer Diagnostics
Typical Digital Output Signals include:
- Scan complete
- Muliplexer channel number (up to 9)
- Product number (up to 32)
- Identification result (pass/fail)
- Qualification result (pass/fail)
- Global instrument error
- Diagnostic result (pass/fail)
- Out of tolerance
- Running diagnostics indicator
Specifications
Dimension
16” (1) X 13" (w) X 5" (h)
I/0 Connections
Three fl” conduit holes in rear panel for wiring into and out of I/0 module
Analog Devices
Grayhill (70G-01420)
scaleable 4-20mA, 8 analog
channels Standard, up to 24 channels
available (8 modules per rack)
Communications
Serial RS232
Input Power Requirement
120/220 volts, 50/60 Hz
Digital Input Devices
Miniature Grayhill (70M-IDOS) polarized 3-32vdc Input
9 Inputs supplied
Digital Output Devices
Miniature Grayhill DC Output (70M-ODC5R)
dry contact, 100vdc/120vac max load voltage
15 Outputs supplied
Wiring Recommendation
Alpha XTRA Guard 2, No. 25299
9/pr. 20 AWG twisted pair, foil shielded plus overall
tinned copper braid with drain wire
(recommended for both analog and digital)
현재위치 : Home > 판매완료된장비
