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H40.0.01.6C-09
Operating Manual GMH 3330
Page 10 of 16
7
Measurements Using Flow Measuring Probes STS005 / STS020
Two types of measuring probes are available for flow speed measurements:
Please note:
-use
STS 005
to measure
water
flow
-use
STS 020
to measure
air
flow
Incorrect use will result in incorrect measurements!
Please observe max. measuring ranges for flow measurements!
-STS 005: 0.05 ... 5.00 m/s (water)
-STS 020: 0.55 ... 20.00 m/s (air)
Higher speeds may destroy the measuring head or may, at least, permanently influence measuring accu-
racy.
An arrow on the measuring head indicates the required flow direction.
Flow measuring probes are 'free-jet calibrated', i.e. the diameter of the flow channel has to be 5 times
bigger than the diameter of the flow measuring head (= approx. 5 cm, otherwise measuring errors up to
40%).
When evaluating the measuring results please also note that in a channel the flow speed is usually higher
in the middle of the channel than at its edges. Therefore, use appropriate tables to calculate air flow by
means of flow speed.
Averaging for Flow Measurements:
When taking flow measurements fluctuations tend to be quite high. To be able to display a stable measur-
ing value two averaging functions have been integrated in the instrument.
Continuous Averaging
The average value displayed has been calculated from the past few measurements conducted during the
averaging time set. After the instrument has been switched on, the time remaining till expiration of the
averaging time will be displayed at the bottom line of the display. The min. and max. values memorized
refer to the minimum and/or maximum average value displayed.
Average Hold
As soon as the GMH3330 instrument has been switched on the device starts calculating the average flow
value during the averaging time. During measuring the
current measuring value
will be shown in the top
line of the display while the bottom line shows the remaining measuring time. As soon as measurements
have been completed the
average value
will be displayed and the device will switch to the HOLD mode.
The min. and max. values memorized refer to the minimum and/or maximum measuring value established
during averaging.
To start a new measuring series press the key "Store" (key 6).
Additional Measurements with any NiCr-Ni-Temperature Probe at T2:
Use temperature channel T2 to take measurements of medium temperature, for example. The value
shown ist not an average value.