12
User Manual EE872 Modular Probe for CO
2
, RH, T and p
6.2 Changing the Filter Cap
In a dusty, polluted environment it might be necessary to replace the filter cap once in a while. In most
of the cases, a clogged filter shows visible contamination or dirt. Longer response time of the CO
2
measurement also indicates a clogged filter cap. In such cases, replace the filter by a new, original one,
see data sheet “Accessories”.
Procedure:
»
Turn the filter cap counter-clockwise for removing it.
»
Install the new filter cap fingertight by turning it clockwise.
6.3 EE872 Adjustment or Calibration with Reference CO
2
Gas
Definitions:
Adjustment: the specimen is brought in line with the reference.
Calibration: the specimen is compared with a reference and its deviation from the reference is documented.
For EE872 calibration or adjustment with reference CO
2
gas use the calibration adapter HA010785 (not
included in the scope of supply, see data sheet “Accessories”).
calibration adapter protection cap
rubber
caps
Fig. 6 Calibration adapter HA010785 (with mounted rubber caps for use as protection cap)
Procedure:
»
Remove the filter cap and install the calibration adapter onto the probe.
»
Connect the calibration gas to one of the two connection nipples. The gas fed into the calibration
adapter shall freely flow out through the second nipple.
»
Set the flow rate to 0.1 ... 1.0 l/min and consider a stabilization time of 10 min.
Please note:
• For best accuracy of the calibration procedure, the temperature difference between reference gas
and probe should be as low as possible.
• Adjustment/calibration shall be performed with the factory settings activated concerning sensing
module heating and pressure compensation.
6.4 Protection of EE872 During Site Cleaning Application
The calibration adapter (HA010785) can also be used as a protection cap, for instance if the device
remains on the measuring site during cleaning operations. For this purpose, close both nipples with the
supplied rubber caps.
In case the probe is removed from the site, it is recommended to apply the protection cap for the M12
cable socket (HA010781) and the one for the EE872 M12 plug of (HA010782).
