20
back on until the humidity level drops back to slightly below the
set point. The System will continue to cycle to maintain the
desired humidity to within
±
3% RH of the set point.
5. If the Model 5112 Controller is to be used as a humidity
indicator only (no humidity control), place the DEHUMIDIFIER
switch to OFF. The system now becomes a humidity level meter
(hygrometer) only.
6. Frequent on/off cycling of the dehumidifier may be indicative of
a poor test chamber seal or defective gloves. The chamber
should be thoroughly inspected to determine where the leak(s)
are located and the problem corrected.
3.2.5 Calibration
The Model 5112 Controller is calibrated prior to leaving the factory.
However, as with all temperature and humidity measuring
instruments, they must be calibrated periodically to maintain
specified performance levels. Calibration should be checked at
least one or two times a year depending on the operating
conditions and the required measurement accuracy. The Model
5461 does not require calibration.
NOTE:
If returning to the factory for recalibration or repair, first obtain
a RMA number from ETS by calling 215-887-2196 Ext. 220.
Calibration of the Model 5112 is performed as a complete unit.
Turn on the power and allow at least 5 minutes for the instrument to
warm up. Place the DEHUMIDIFY switch in the OFF position then
follow the procedure described below.
Calibration of the Controller requires a known calibrated reference
sensor for comparison. As an alternative, certified calibration salt
solution cells can also be used.
The Model 5112 is calibrated by comparing the relative humidity
reading with the reading of a known calibrated reference. The
reference sensor should be placed next to the Model 5112 sensor
and allowed to stabilize for at least 30 minutes before making any
adjustments to the sensor electronics.
Calibration can be performed either in the test chamber or in a
separate calibration cell.
1. Remove the Sensor from its mounted position. If the Sensor is
to be calibrated in the chamber, place the reference sensor next