Thunder Scientific
Model 2500 Humidity Generator
NIST
標準認可 "雙壓力"
標準低濕度產生機
- Accuracy ± 0.5 % RH
- Traceable to NIST
- Based on NIST Proven Two-Pressure Principle
- Self Contained and Mobile
- Automated Control of User Setpoints
- Shipped with ControLog(TM) Automation Software and
Humicalc(R) Humidity Conversion Software
- Computerized Internal Transducer Calbration
- Automatically Applies Enhancement Factors
- RS-232C Serial Interface
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The Model 2500 Humidity Generator is a self contained system capable of
producing atmospheres of known humidities using the fundamental, NIST proven,
"two-pressure" principle. This system is capable of continuously supplying
accurately known humidity values for instrument calibration, evaluation, and
verification, as well as for environmental testing.
Simply apply power and the 2500 will power-up ready
to generate. Humidity setpoint values are input by the operator from the front
panel keypad and are limited only by the range of the 2500 humidity
generator.
Relative humidities are calculated from the
measurements of pressure and temperature with the following formula:
Formula: %RH = fs/fc x
es/ec x Pc/Ps x 100
To generate a known humidity, the computer controls
the pressure ratio Pc/Ps utilizing the enhancement factor
ratio fs/fc and the effective degree of saturation
es/ec. Humidity produced is solely dependent on the
measurement of pressures and temperatures and does not rely on any other device
(such as a dew point hygrometer, psychrometer, or humidity sensor) for the
measurement of water vapor content. Precision humidity generation is determined
by the accuracy of the pressure measurements and on the accuracy and uniformity
of temperature throughout the generating
system.
General Information
The Model 2500 Humidity Generator operates using an
on board multifunction CPU in conjunction with other peripheral cards to perform
calculation and control functions. The embedded computer control system allows
the 2500 to generate known humidity levels unattended, freeing the operating
technician from the task of system monitoring and adjustment. A computer and/or
printer may be connected via the bi-directional RS-232C interface ports allowing
remote setpoint control and continuous acquisition of system data.
Humidity and temperature setpoint values are input
by the operator from the front panel keypad while visual indications of system
status are displayed in real time on the liquid crystal display.
Control / Display
Screen
All Control and measurement parameters critical to
the operation of the humidity generator are displayed on this screen. Each
parameter in the leftmost column is identified with a brief title and
corresponding units. The generator operates in a variety of user selectable
pressure, temperature, and flow units. Some of these are °C, °F, psi, "Hg, Tor,
mbar, kPa, l/m, l/h, cfm and cfh. Humidity is calculated and displayed in
percent relative humidity (%RH). The asterisk in the leftmost column indicates
the active humidity control parameter. The "SetPnt" column lists control
setpoints and the "Actual" column lists all of the measured data and calculated
parameters of the generator.
Temperature Control: The system utilizes a
fluid jacketed test chamber for extremely stable temperature control.
Temperature setpoint control is attained by controlling the temperature of the
circulating fluid medium that jackets the test chamber and associated humidity
generation components. Chamber and saturation temperatures are governed by this
medium and are digitally controlled by the computer at any value between 0 °C
and 70 °C using PID (proportional-integral-derivative) algorithms.
Pressure and Flow Control: Pressure control
and mass flow control are accomplished through computer actuation of
electromechanical valve assemblies. Pressure and flow are measured continuously
and controlled using PID algorithms similar to those employed in temperature
control.
Calibration: The 2500 humidity generator
employs an integral programmatic calibration scheme allowing the temperature and
pressure transducers to be calibrated while they are electrically connected to
the humidity generator.
Calibration / Display Screen
Coefficients for each transducer are calculated by the
computer and stored in the system's nonvolatile memory until the next
calibration is performed.
Specifications
|
Relative Humidity Range: |
10% to 98% |
| Relative Humidity Resolution: |
0.02% |
|
Relative Humidity Accuracy: |
±0.5% @ PcTc(k=2) |
| Chamber Temperature Range: |
0°C to 70°C |
|
Chamber Temperature Range: (Optional) |
-10°C to +70°C |
| Chamber Temperature Resolution: |
0.02°C |
|
Chamber Temperature Uniformity:** |
±0.1°C |
| Chamber Temperature Accuracy: |
±0.06°C |
|
Chamber Pressure Range: |
Ambient |
| Gas Flow Rate Range: |
2 to 20 slpm |
|
Gas Type: |
Air or Nitrogen |
| Gas Pressure Rating (MAWP): |
175 psiG |
|
Heating/Cooling Rate: |
2.5 Minutes Per °C Average |
| Chamber Window: |
6" x 6" (152 mm x 152 mm) Window in Door |
| |
|
|
Physical Dimensions: |
|
|
2500 |
19" (483 mm) H
33" (838 mm) W
20" ( 508 mm) D
|
|
2500S |
19" (483 mm) H
36" (914 mm) W
20" (508 mm) D
|
|
2500ST |
22" (559 mm) H
36" (914 mm) W
23" (584 mm) D
|
|
Physical Dimensions of Cart: |
|
|
2500 |
33.25" 9845 mm) H
40" (1.20 m) W
23" (584 mm) D
|
|
2500S |
33.25" (845 mm) H
43" (1.09 m) W
23" (584 mm) D
|
|
2500ST |
33.25" (845 mm) H
43" (1.09 m) W
26" (660 mm)
D |
| |
|
|
Physical Dimensions 2500 With Cart: |
|
| 2500 |
53" (1.35 m) H
40" (1.20 m) W
23" (584 mm) D
|
|
2500S |
53" (1.35 m) H
43" (1.09 m) W
23" (584 mm) D |
| 2500ST |
56" (1.42 m)
43" (1.04 m) W
26" (660 mm) D
|
| |
|
|
Chamber Dimensions: |
|
| 2500 |
12" (305 mm) H
12" (305 mm) W
10" (254 mm) D
|
|
2500S |
12" (305 mm) H
15" (381 mm) W
10" (254 mm) D
|
| 2500ST |
15" (381 mm) H
15" (381 mm) W
12" (305 mm) D |
| |
|
|
Utilities: |
|
| Electrical Power: |
100/120 V~, 15 A, 50/60 Hz |
|
(Optional) |
200/240 V~, 8 A, 50/60 Hz |
| Air Compressor: |
100/120 V~, 5 A, 50/60 Hz |
|
(Optional) |
200/240 V~, 2.5 A, 50/60 Hz |
| Air Supply (External): |
Clean, Oil Free Instrument Air
@ 175 psiG & 20 slpm |
| |
|
|
Environmental: |
|
| Operating Temperature: |
15°C to 30°C |
|
Storage Temperature: |
0°C to 50°C |
|
Humidity: |
5 to 95% Non-condensing |
|
