Leave the HMK15 calibrator and the probe at the calibration site for at least 30 minutes before starting the calibration in order to let the probe temperature stabilize to room temperature.
With lithium chloride, it is not necessary to use the thermometer, as the humidity reading changes only very slightly in temperature range +25 ... +30 °C (+77 ... 86 °F). However, if you use the thermometer, make sure that the sleeve is in the correct position and insert it into the 13.5 mm (0.53 in) hole of the LiCl salt chamber.
See also HMK15 chamber lid options.
|Handle the thermometer as little as possible and do not touch the measuring end. Press the thermometer downwards until it passes the O-rings. The thermometer is correctly in place when you feel a resistance while pressing it downwards.
Remove the grid or filter protecting the sensor. Take care not to damage the
When calibrating HPP271 or HPP272 probes, or when using lid 253277SP with any 12 mm diameter probe, leave the grid or filter on.
Some 12 mm (0.47 in) probes need a calibration adapter if used in one of the 13.5 mm
(0.53 in) holes of spare part chamber lid 271550 (see HMK15 chamber lid options). The calibration adapter prevents
the sensor from soaking in the salt liquid.
In case you need a calibration adapter, remove the grid or filter and replace it with the adapter. Two adapters are provided on the base plate of the HMK15.
Remember to check from the user guide of your device if a calibration adapter is needed.
If the sensor accidently soaks in salt liquid, remove it quickly and rinse with clean water. Let the sensor dry before taking into use again.
- Insert the probe into a suitable hole of the LiCl salt chamber. Press it downwards until it passes the O-rings. The shorter the time the hole stays open before inserting the probe, the shorter the stabilization time required.
- Wait until the humidity reading stabilizes; this takes about 10 … 30 minutes.
- Read the salt chamber temperature from the thermometer and then read the closest humidity value from the calibration table (Greenspan's Calibration, LiCl solution).
- Adjust the dry end (DRY, offset) to correspond to the value given in the calibration table.
Insert the thermometer into the 13.5 mm (0.53 in) hole of the NaCl salt chamber.
When calibrating probes that are being used for long term measurements (over 1 hour) in high humidities (90 … 100 %RH), use the K2SO4 salt as the high end reference.
- Insert the probe into a suitable hole of the NaCl (or K2SO4) salt chamber. The shorter the time the hole stays open before inserting the probe, the shorter the stabilization time required.
- Wait until the humidity reading stabilizes; this takes about 10 … 30 minutes. Note that in high humidities the risk for errors increases. Therefore, the stabilization time should be longer (approximately 20 … 40 minutes).
- Read the salt chamber temperature from the thermometer and then read the closest humidity value from Greenspan's calibration table, NaCl or K2SO4 solution. See Table 1.
- Adjust the wet end (WET, gain) to correspond to the value given in the calibration table.