Vaisala HMK15 Humidity Calibrator is a suitable humidity reference for HMP Series probes. When preparing the salt solutions and using the calibrator, follow the general instructions in the HMK15 User Guide (M210185EN) to avoid common sources of calibration error.
HMK15 with HMP3, HMP4, HMP5, HMP7, and HMP8 probes
Before inserting the probe head in the salt jar, remove the filter and inspect the sensor element. If the leg pins of the sensor are longer than 7 mm (0.28 in), attach the 211302SP calibration adapter. This prevents the sensor from being submerged in the salt solution. Composite sensors typically have long leg pins.
211302SP is the longer of the two adapters included with HMK15. With this adapter attached, use the 13.5 mm hole on the salt jar cover.
12 mm (0.47 in) diameter probes where the leg pins are shorter than 7 mm can be inserted in the salt jar without an adapter. Note that you can still use the 218377SP calibration adapter to fit a 12 mm probe in the 13.5 mm hole. This allows you to have multiple probes inserted in a salt jar at one time.
| CAUTION Sensors on the probe head are vulnerable to damage when the filter is removed. Handle the probe carefully and avoid touching the sensors. |
HMK15 with HMP1 and HMP9
HMP9 calibration adapter for HMK15 (item code ASM213801) is required to fit the HMP9 probe head to the 12 mm hole on the HMK15 salt jar.
The same adapter does mechanically fit the HMP1 as well. However, use of HMK15 with HMP1 is not recommended due to additional temperature error caused by heat conduction from the electronics of the probe body. HMP1 should be calibrated so that the entire device is in the calibration environment, not just the probe head. Vaisala's calibration service is a good option for maintaining the accuracy of HMP1.
| You can use HMK15 with HMP1 and achieve an accurate calibration if the probe is unpowered during stabilization. This is typically only practical for 1-point calibration. |