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The factory-set values are:
NOTE
Set-point 1 : 10PPM
Set-point 2 : 20PPM
Set-point 3 : 30PPM
Set-point 4 : 50PPM
Safety set-point
The fifth set-point made available by the HID is a set-point dedicated
to protect the PHD-4 against excessive exposure to high
concentrations of helium.
Accessing the “Safety Set-point” item, it is possible (as for set-points
1-4) to enable operation and to modify the tripping threshold in the
range 2PPM-250PPM in HS and 100PPM-600PPM in LS (factory
settings 100PPM in HS and 400PPM in LS).
The Safety set-point menu also contains the item:
Safety actions
Backflow valve (factory setting: active)
Heater OFF
This menu makes it possible to manage sensor protection actions.
Protecting the sensor means restricting the flow of tracer gas
(helium) to the amount strictly necessary to trace leaks.
Backflow valve – Activation of the backflow valve is part of the
factory settings. This device is tripped when the threshold set is
exceeded and inverts the flow sampled sampling the gas from the
outlet port and then discharging this through the probe normally
used for sampling.
PHD-4 Portable Helium Detector User Manual
Technical Information
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87-900-120-01 (F )
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User Interface
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