H61.0.02.6C-04
User’s Manual GMH3151
page 5 of 12
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GREISINGER electronic GmbH
2.1 Different Kinds Of Measuring: „rAtE-Slo, -P.dEt, -FASt“
Three different kinds of measuring pressure are supported. Two of them (P.dEt and FASt) are working with
high measuring frequency of more than 1000 measurings per second.
2.1.1 rAtE-Slo:
Standard
Measuring
Measuring rate 4Hz, averaging and filter functions are active.
Application:
Measuring of slowly changing or static pressures, e.g. measuring of leakproofness, athmospheric pressure...
Highest accuracy, high noise immunity (EMI and unstable measuring signals), low power consumption.
2.1.2 rAtE-P.dEt: Peak
detection
Measuring rate >1000Hz, the value is displayed unfiltered.
Application with logger function: Measuring of short pressure peaks or fast changing pressures with a
resolution of < 1ms. The cyclic logger function records the arithmetic mean value, the highest and the lowest
peak of the referring time interval.
Attention: higher power consumption, measuring is sensitive to noise (EMI,..).
2.1.3 rAtE-FASt:
Fast filtered measuring
Measuring rate >1000Hz, the value is filtered slightly (higher noise immunity than P.dEt, small peaks will be
filtered out), apart from that identical behaviour like P.dEt.
2.2 Measuring Of Water Level – Display Unit [m]
When using suitable waterproof pressure sensors the unit [m] for meters of water can be set in the menu
“Unit“. 10m of water are roughly 1 bar over pressure. Measurings can be made e.g. like described below :
•
With one abs. pressure sensor (SL oFF!): Press ‚Tara‘ when sensor is at ambient air and then bring
sensor to the depth to be measured. The display shows now the depth in [m].
•
With one rel pressure sensor: bring tube connection for lower press. in contact to ambient air by means
of a tube (no water contact!) and bring the sensor with its open press. connection for higher pressure to
water depth to be measured (display and is compensated for pressure changes in ambient air).
2.3 Sea Level Correction For Absolute Pressure Sensors
The device displays the absolute pressure. This is not necessarily the same like the values given by weather
stations! The weather stations‘ values are giving the pressure at sea level. Usually the sensor is placed
above sea level and therefore, if the value at sea level(zero) is to be measured, the pressure loss resulting
from the actual level above sea level has to be considered! To correct the measuring display activate the
„Sea-Level-Function“ (SL, p.r.t. chapter 2, setting is only possible, if the abs. pressure sensor is connected to
sensor socket 1). Then enter the altitude above sea level of the sensor‘s location in meters (Alti, p.r.t. chapter
2). When activated, the display shows the SL-arrow and the device displays the pressure value at sea level.
2.4 Averaging Function
The averaging function concerns the display values (LCD and interface). It is completely independent from
the averaging of the logger function, please don’t mix them up!
The averaging integrates the measuring values during a selectable period of time and then calculates the
average display value. It is independent from the selected kind of measuring (slow, fast, peak detect).
As long as not enough values are collected (selected averaging time) to calculate a average value, the upper
display shows “----“, the lower display a ‘countdown‘.
During an active low-power-logging procedure the averring is always deactivated
Function of min/max-value memory during averaging:
- If averaging is activated and slow measuring is selected (rAtE-Slo), the min-/max-value memory refers to
the average display value.
-
If averaging is activated and fast measuring is selected (rAtE-FASt or P.dEt) , the min-/max-value memory
refers to the internal measured values (fast peaks can be detected).
