Siemens 3TK28, Руководство пользователя, Страница: 96 / 206

Description of the individual safety relays
3.6 3TK28 safety relays with relay enabling circuits
3TK28 safety relays
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Manual, 07/2016, NEB926157502000/RS-AB/003
3.6.8 3TK2830 expansion unit
3.6.8.1 Applications
Applications of 3TK2830 expansion unit
The 3TK2830 is used to expand the enabling circuits. You can use it together with all 3TK28
basic units. The maximum achievable performance level PL / Cat. in accordance with
DIN EN ISO 13849-1, or SILCL in accordance with IEC 62061 is equivalent to the
performance level PL / Cat. / SIL of the basic unit if the external circuitry (cable connection
between basic unit and expansion unit) is failsafe.
3.6.8.2 Description of function and connection information
The 3TK2830 has four safe enabling circuits as NO circuits and one positive-action NC
circuit. Two LEDs indicate the operating state.
The 3TK2830 is controlled via any enabling circuit of the basic unit. The NC circuit 51/52 of
the 3TK2830 is looped into the feedback circuit of the basic unit.
The 3TK2830 expansion unit is checked for correct functioning by means of the feedback
circuit of the connected basic unit.