Sierra RedyCompact Meter, Инструкция по эксплуатации, Страница: 11 / 73

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1.13.
Documentation and Cables Supplied
A printed quickstart quide is shipped together with each device. However, we recommend to visit
our website to obtain the latest version of the manual and the latest firmware version for the
RedyCompact .
Every device comes with a USB A to USB Micro-B cable. This cable can be used to power the unit
and to upgrade the firmware.
We ship the device with the following accompanying documentation:
•
1 factory calibration certificate per ordered calibration
•
Final inspection report
•
USB cable + 1 x AA battery (if battery powered)
•
Quick Install Guide
•
Product Information Card with links to current instruction manual
1.14.
The Measurement Principle
The thermal mass flow measurement principle is particularly suitable for the measurement and
control of clean and dry gaseous media. The most significant advantage is that the measurement
process measures the real mass flow and is largely independent of temperature and pressure.
Stated simply, the thermal measurement principle measures the heat transport by gas flowing past.
In the case of
red-y mass flow measuring instruments, a constant heat input gives a flow-
dependent temperature difference (
∆T). Two temperature sensors are positioned in the measuring
channel (T1, T2), one before the heating system (H) and one after it (see Figure 1).
If there is no flow, the heat spreads symmetrically in directions T1 and T2. The temperature
difference T1-T2 is therefore zero.
Flow rates > 0 create a temperature difference. The sensor T1 at the inlet is cooled by the gas
flowing past it, and the temperature of the second sensor T2 rises due to the heat drawn from the
heating system.
Figure 2: Measurement Principle
Figure 1: Sensor Operation