Description
The S904 Series are completely stand-alone and transportable calibrators for humidity
sensors, requiring no external services other than mains power. The calibrator is capable
of humidity generation over the range of 10-90% RH, with temperature control from
+10 to +50°C (+50 to +122°F). The calibration chamber features 5 interchangeable
ports to accommodate virtually any brand, type or model of sensor. This calibrator is
ideal for companies or organizations looking to calibrate large numbers of probes in a
laboratory or field setting.
The environment within the insulated calibration chamber is temperature controlled
using a 4-zone fan assisted Peltier arrangement for maximum stability, and minimum
temperature gradient. The humidity of the circulating air is precisely regulated using
a closed-loop control system that functions by proportionally mixing flows of dry and
saturated air.
Two highly visible LED panels display the current humidity and temperature within the
calibration chamber. The response time to a humidity or temperature step change is
typically less than 10 minutes, so a simple 3-point calibration can be carried out in
under an hour.
The S904 Series is easy to maintain. The desiccant changes color to indicate when it
needs to be recharged and this is visible through a clear window on the front of the
unit. Recharging the desiccant is simply a matter of heating it in a conventional oven
at +130°C (266°F) for 3 hours. The water reservoir at the front of the unit shows
the current saturation fill level, and makes it easy to top-up with distilled water when
required. The only external service required is a single phase power supply.
There are two versions available:
•S904
•S904D
With the S904D version, the humidity and temperature set points of the chamber can
be controlled with the supplied PC application software, enabling the operator to create
completely automated calibration profiles for unattended laboratory operation. The
software also gives the ability to monitor, chart and log data from the probes connected
to the S904D or application software for later analysis. Alternatively, the set points can
be controlled manually with the front panel controls - making the S904 Series ideal for
field calibrations where a PC is not available.
Comparison of the S904 and S904D
The S904D has the Data Acquisition connector on the rear panel, and a blanking plate
fi tted to the front panel, as shown bellow.
The S904D also features a USB, and an RS232 port on the rear panel, for communication
with the LabVIEW® application software.
System Components
No. Description
1.Chamber door
2.Water reservoir
3.Desiccant cell and indicator window
4.Relative humidity set point (%rh)
5.A: Manual/Auto switches for relative humidity / temperature control
MAN: Setpoint is set by switch 4 (humidity) and switch 6 (temperature)
AUTO: Remote control of relative humidity / temperature set points
B: ON/OFF switches for relative humidity / temperature control
6.Temperature setpoint (°C)
7.Humidity level indicator
8.Temperature level indicator
9.Humidity control indication LED: Humidify (yellow) / De-humidify (green)
10.4-Zone chamber temperature control indication LEDs:
Heating (yellow) / Cooling (green)
11.Data aquisition connector / Blind plate (S904D)
12.Ventilation fans
13.Electrical mains connector, on/off switch and power input fuse
14.Data acquisition connector (S904D)
15.USB connection (S904D)
16.RS232 connection (S904D)
Accessories
The S904/D humidity and temperature generator is delivered with the following standard
accessories:
•Bottle of distilled water
•Desiccant cell filled with silica gel
•HT961T00 control probe
•Chamber door (according to customer specification)
•IEC mains cable
•Calibration certificate for internal reference probe
•Certificate of conformity (graph)
•User’s Manual
•USB cable (S904D)
•LabVIEW® software (S904D)