Introduction; Description - Michell Instruments OptiCal User Manual

OptiCal User's Manual
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INTRODUCTION

1.1

Description

The Michell OptiCal is a stable and accurate calibration solution for humidity sensors
over the 10 to 90%RH and +10 to +50°C (+50 to +122°F) range. The stand-alone,
transportable calibrator requires no external services other than mains power, and
features an integrated chilled mirror reference instrument to enable the operator to
perform calibrations that are traceable to national standards.
The calibration chamber features fi ve interchangeable ports to accommodate virtually
any brand, type or model of sensor. The environment within the insulated calibration
chamber is temperature controlled using a four-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 fl ows of dry and saturated air.
A bright and clear VFD (vacuum fl uorescent display) displays the parameters measured
by the reference instrument in various relative and absolute humidity units, alongside
the temperature within the chamber.
The humidity and temperature set-points can be controlled either manually or
automatically as part of a calibration program. Manual control is achieved by the switches
on the front panel. Response time to a humidity or temperature step change is typically
quicker than ten minutes. The supplied application software allows calibration programs
to be created, enabling automatic time-based control of temperature and humidity set
points. The software also allows the user to monitor, chart and log calibration reference
data on a PC for later analysis.
The desiccant changes color to indicate when it needs to be recharged, and is visible
through a clear window on the front of the unit. Recharge the desiccant following the
instructions in Section 2.4. The water reservoir at the front of the unit shows the current
saturator fi ll level, and makes it easy to top up with distilled water when required (refer
to Section 2.2). Apart from periodic calibration of the chilled mirror reference, no other
maintenance is necessary. The only external service required is a single phase power
supply.
Michell Instruments
INTRODUCTION
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