Lamtec ETAMATIC, Manual

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9 Appendix
9.19 Feedback at Three-point-step Outputs
9.19.1 Joining with positive locking
Since the ETAMATIC, in the case of three-point step channels, adjusts the damper until the
actual value is equal to the set-point value. The feedback potentiometer must always reliably
correspond to the damper position.

The damper motor potentiometer connections must be positive interlock connections, i.e. not
able to rotate.
In addition you must use potentiometers with high quality standards (see next page). If one of
these two points is not given, you must use two independent potentiometers (not dual-operat-
ed potentiometers) per channel for the feedback.
The motor damper connection must always be a positive interlock.
WARNING!
The connection has to be designed in that way that the maximum torque of the motor could
not break the connection under any condition.
Fig. 9-28 example of positive potentiometer connection
9.19.2 Fail-safe Feedback
In the case of single-channel feedback of TPS outputs, only authorised potentiometers may
be used. These must be switched directly.
9.19.3 Examples of potentiometers
Example of potentiometers:
The following potentiometers are authorised for use as solo feedback in the case of

ETAMATIC, on condition that they are positively connected to the damper:
Manufacturer Type Rating
Novotechnik SP-Serie Rating: 5 k Ω *
Contelec PL 240 Rating: 1 k Ω - 5 k Ω *
Contelec PL 310 Rating: 5 k Ω *