Instruction sheet

Hh 48/98

Transfer Element of the 2nd Order

734 095

1. Prescribed use The training panel is part of the modular TPS 8.2 training system and permits the investigation of an oscillating transfer element of the 2nd order, i.e. a two-stage low-pass filter with variable time constants and a joint attenuation factor of approx. 0.1 (in the case of oscillation) up to 3 (“crawl mode”).

2. Location of use Operation in dry rooms which are suitable for experimentation with electrical equipment or installations.

3. Description

1 Socket for +15 V supply voltage 2 Socket for ground terminal 3 Socket for –15 V supply voltage 4 Input socket of the transfer element of the 2nd order 5 Input socket for the reset signal of the internal low-pass element set to the „zero“ initial condition

6 Socket for further transmission of the reset signal 7 Output socket of the transfer element of the 2nd order 8 Joint fine adjustment of the time constants 0.1 s - 0.2 s - 0.3 s for the two low-pass elements 9 Joint multiplication factors x0.1 - x1 - x10 - x100 of the time constants for the two low-pass elements

bl Three-turn fine setting of the attenuation factor d between 0.1 and 3 bm Overshoot indicator of the output signal for a level > ±10 V

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4. Function The transfer element of the 2nd order realizes the differential equation

T 2 x˙˙a (t ) + 2 aTx˙ a (t ) + xa (t ) = x e (t ) where the time constants T1,2 are in the range from a range of 0.01 s up to 30 s. Here the attenuation factor d can be set very precisely to a value between 0.1 and 3, i.e. in the order of

d

2

< 1, d

2

= 1 and d

2

> 1.

With a reset signal greater than +5 V (e.g. TTL level) applied to sockets 5 or 6 the transfer element is switched to the initial condition “output variable zero“. This operating mode is advantageous for the recording of transient functions, e.g. usint the test function generator, cat. no. 734 40 or using the CASSY software CBC 8.2 process control technology, cat. no. 728 322.

5. Putting into operation and control Insert the training panel of the transfer element of the 2nd order into the panel frames and connect a suitable ±15 V power supply, e.g. cat. no. 726 86. The following steps must be carried out for automatic control operation: Connect the input socket 4 to the output of a suitable controller from the TPS 8.2 program or to the output socket Y of the CASSY interface, here also connect up the reset input 5, 6if needed. Connect the output socket 7 to the signal input for the controlled variable on the controller or the input socket B of the CASSY interface.

6. Technical data Power supply: Current consumption:

±15 V ±30 mA

Input and output signal range:

±10 V

7. Recommended experiment literature F.H. Effertz, H.-W. Hüsch Fundamentals of Automatic Control Technology II, Volume 2: Experiment-based Fundamentals of Automation Systems Section 2.4 The Laplace transform and relationship between frequency response and characteristic time functions Leybold Didactic GmbH, Huerth 1998, cat. no. 568 222, ISBN 3-88391-305-7

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