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Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
17 Engineering notes
15.10.2002
·
With a change of 0.4 %, the change in voltage over the entire angular rotation must
be 40 mV
±
10 mV
D
U [V]
= 0,4 %
U
78721d06/0501
[%]
)
D
Fig. 38
Required microlinearity of the feedback potentiometer
·
The potentiometer wiper must be able to carry a current of
£
0.1 mA. The electrical
contact must also be suited for very small currents
78721d07/0501
U10
B..
M
I 0,1 mA
£
RVW25
Fig. 39
Required contact rating of the potentiometer wiper
·
The potentiometer should be capable of exceeding 1 million cycles
Since the above requirements cannot be met with wire potentiometers, this products
uses
special conductive plastic potentiometers
of high quality.
If potentiometers of other manufacture are used, it is
recommended to always install
conductive plastic potentiometers.