| DG-4 relative humidity controller 
The DG-4 relative humidity controller and dewpoint controller allows you to control the water vapor content of an air stream in several versatile ways. It can be operated in either a locally controlled mode, or a computer-controlled mode that allows the generation of complex water vapor ramps and steps. In relative humidity controller mode, the DG-4 relative humidity controller reads the temperature of the area in which relative humidity control is required, using a supplied thermistor probe. Using a saturated air stream as its input (saturator supplied with unit), the DG-4 then adjusts the water vapor content of the air stream to yield the precise set relative humidity. It does so by calculating the saturated water vapor pressure at the regulated air, using the measured temperature at that point. Then, it calculates the target water vapor pressure corresponding to the desired relative humidity entered by the user. Finally, it calculates the dew point corresponding to the target water vapor pressure and regulates its internal condensing unit at that temperature, using a space-age solid-state heat pump. The result is accurate, consistent relative humidity control even in the face of fluctuating environmental temperatures. This is a unique capability of the DG-4 that is invaluable for many kinds of biological experimentation, product testing, protein crystallography, and so on. Alternatively, the DG-4 can be used as a dewpoint regulator (range 1 - 45 C) or as a water vapor partial pressure regulator. Air flow rates ranging from about 25 ml/minute to 5 liters/minute can be used without affecting the system's regulation efficiency. Condensed water is evacuated from the condenser by a miniature diaphragm pump at user-settable intervals. Alternatively, a simple plumbing change allows the user to remove condensate slowly and continuously with a user-supplied peristataltic pump. All of the instrument's functions are accessed via high quality rotary encoders. We have paid particular attention to making their operation as intuitive and flexible as possible. The DG-4 is extremely easy to operate. All adjustments and settings are permanently retained in the absence of power. Analog and serial data outputs are standard. | DG-4 Specifications: | | Technology: Solid state heat pump (Peltier effect) | | Dewpoint Range: 1-45 degrees C, in 0.1 C increments | Relative Humidity Range: At 25 degrees C target temperature, approximately 20 - 95+ RH% attainable; settable from 0-100%RH in 0.1%RH increments
| | Water Vapor Pressure Range: 0.65 kPa - 9.6 kPa, in 0.01 kPa increments | Accuracy and Resolution: Dewpoint accuracy 0.25 C, resolution 0.01 C
| Regulation: PID (Proportional Integral Derivative), dewpoint deviation < 0.05 C RMS typical
| | Flow Rate: 25 ml/minute to 5 liters/minute | | Condensate removal: Miniature diaphragm pump, user-settable actuation from 1/minute to 1/30 minutes, actuation duration user-settable from 1 sec to 30 sec | | Analog Output: Multi-range for relative humidity, dewpoint or water vapor pressure; 0-5V output with 16 bit resolution | | Serial Data Output: Comma delimited ASCII string of all measured parameters, standard RS-232 serial, polled or auto-sent at user definable intervals from 0.5 - 600 seconds. | | Internal A/D Conversion: 16 bits | | User Interface: Intuitive menu system backed by nonvolatile memory of user settings | Panel Display: Digital 2-line alphanumeric LCD, simultaneous display of set and read values
| | Tubing Fittings: Nickel plated barb fittings for 1/8" (3 mm) i.d. flexible or semi-rigid tubing; other fittings available to special order | | Power Requirements: 12 VDC at 8A. 110VAC or 220VAC adapter supplied | | Operating Temperature: 5 - 35 degrees C, relative humidity non-condensing | | Size/Weight: EDIT!!!!!!!!!!!!!13" x 10" x 4" (33 x 25 x 10 cm); less than 10 lbs (4.5 kg) |
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