Cleaning

The presence of particulate matter, oil films, liquid water, or the residue from water drops on the device optics can adversely affect its performance. The environmental guard is designed to prevent solids or liquids from reaching the monitor's optical system. Heating elements are also incorporated into the unit to prevent water condensation. Under severe conditions, however, some material may collect on these surfaces and it may be necessary to occasionally check and clean the windows.

Figure 21 Remove Environmental Guard

1. Remove the environmental or flow cap.

Figure 22 Light Path Obscuration

2. Place an opaque object (piece of paper, two fingers, etc.) between the light source window and the mirror to completely obscure the light path for two to three seconds (→ Figure 22 ). ○ If the opaque object is left in the light path for longer than 10 seconds, an Obscuration fault will be set on the mA output (→ Remote Controller and Menu Sequence). ○ The device enters the Cleaning Mode for 5 minutes.

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The analogue current output will be set to the Cleaning Mode value (→ Remote Controller and Menu Sequence) during this time.

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If monitoring the HART signal, the Cleaning Status bit will be set.

Although both windows are made of a highly durable material that is not easily scratched, avoid excessive pressure when cleaning them. Clean, cotton tipped applicators are recommended to remove material collected on the windows.

3.

Use a dry applicator or one moistened with distilled water to wipe the window and remove dust.

4.

Use an additional clean, dry applicator to remove any residual water.

5.

Use an applicator moistened with isopropyl alcohol to remove heavy deposits of solids, liquids or oil films. Clean the window again with a second applicator moistened with distilled water; then, dry the window with a final applicator.

6.

Avoid using excessive amounts of water or alcohol in the cleaning procedure, and inspect the window to ensure that the entire surface is clean.

NOTE: When the cleaning process is complete, be sure to remove all objects from the light path.

When exiting the Cleaning Mode, the unit returns to normal operation. Note that residual cleaning fluids may result in an elevated signal until completely dry.

7.

Inspect the environmental guard for any blockages, then replace the environmental guard on sensor.

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After cleaning the windows, it is advisable to check the sensor’s response to both zero and calibration gas.

NOTE: If water or isopropyl alcohol is used to clean the sensor's windows, any residue from the cleaning procedure must be completely dissipated before returning the unit to service. Checking the sensor's response to zero gas is the best way to purge residual cleaning materials from the sensor. Ensure that the sensor's reading is stable before zeroing or calibrating the sensor (→ PrimaX IR+ Calibration). Failure to do so could result in inaccurate readings.