Relais lifetime
> 5 million
Inputs 1 + 2 (Opto-couplers):
Voltage range (polarity sensitive): 5 – 30 Vdc (@ 5mA max)
Min. recommended pulse
width
100 msec (Sample interval: 20 msec)
2.16. Calibration
Each measuring device is supplied with a factory calibration report. The calibration is
traceable to American and/or European standards. On request we can also provide
DAkkS calibration (German Accreditation Body).
2.17. Operation with other gases
Each measuring device can store data for up to 3 types of gas or operational states
that need to be defined at the time of purchase.
CMOS gas flow sensors are not linear (The output is linearized) and respond different
to each gas. If the gas or gas composition is different than the gas that the unit was
calibrated for, the unit will not measure accurately. It is possible to program up to 3
different gases and gas mixtures, but this needs to be done at the factory or at a
Vögtlin certified calibration center. Please note that the so- called K-factors as used in
the traditional capillairy MFM/MFC cannot be used for CMOS mass flow meters. Please
contact the factory for additional information.
Note:
Please note that, among other effects, the zero-point error (offset display) will be
higher if the device is not operated with the type of gas, for which it had been
calibrated. A difference in zero indication is also possible if the used pressure is
different than specified.
2.18. Pressure loss
Our thermal mass flow meters have a low pressure drop. The pressure drop depends
mainly on the medium, the pressure conditions and the flow rate. In chapter
you find the pressure drop for the most common gases. Your sales
partner has a calculation program for the other gases. Please note that the size of the
pipes has a large effect on the pressure loss. For example from around 60 ln/min, we
recommend a pipe inside diameter of at least 10 mm.
Please also note that some fittings have a reduced diameter and can cause
considerable pressure drop in your system. Be especially careful with vacuum
applications, please select a relative big pipe diameter).
2.19. Temperature compensation
The red-y compact thermal mass flow meters measure the mass flow of gases, the
result being largely independent of pressure and temperature. In addition to the
fundamental principle an internal sensor measures the gas temperature and, with the
help of a 3-dimensional table of interpolation values, a correction factor is calculated
automatically. The flow indication is thus temperature-compensated.
2.20. Pressure compensation
During calibration, the specified operating pressure is taken into account. Changes to
the pressure conditions may introduce an additional error. This is around ±0.2% per
bar.
Please note that the control behavior is influenced by substantially different pressure
conditions. (relevant for units with an intergrated needle valve only)
2.21. Response time
