H31.0.31.6C-06
User’s Manual GMH3150
page 5
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2.1 Different Kinds Of Measuring: „rAtE-Slo, -P.dEt, -FASt“
Three different kinds of measuring pressure are supported. Two of them are working with high measuring
frequency of more than 100 measurings per second. If one of them was chosen in the configuration (see
above), this will be displayed in the secondary display: „P.dEt“ or „FASt“.
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, atmospheric
pressure...
Highest accuracy, high noise immunity (EMI and unstable measuring signals), low power consumption.
2.1.2 rAtE-P.dEt: Peak
detection
Measuring rate >100Hz, the value is displayed unfiltered.
Application with logger function: Measuring of short pressure peaks or fast changing pressures with a
resolution of < 10ms. 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 >100Hz, 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 Sea Level Correction For Absolute Pressure Sensors
The device displays the absolute pressure measured at the sensor. 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). 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.
2.3 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).
2.4 Power Off Time
If there won’t be pressed any key and no interface communication takes place for the time of the power off
time setting (P.Off), the device will be switched off automatically to save battery power.
If P.oFF = oFF then the automatic switch off is deactivated.
2.5 Address
Up to 10 devices of the GMH3xxx- handheld-family can be connected to a serial interface at once
(depending on interface converter, e.g. GRS3105: 5 devices). To get access to each device the base
addresses of the devices have to be different. For example choose 01 for the first, 11 for the second device
and so on. See also chapter 5.
