Siemens SIMATIC NET PROFIBUS Instruções de Operação descarregar pdf (Página 35)

SIMATIC NET PROFIBUS Optical Link Module OLM V4.0

Operating Instructions, 01/2013, C79000-G8976-C270-03

 Connect self inductances to a suppression circuit. Self-

inductance in relays and fans etc. produces disturbance

voltages that are far higher than the operating voltage.

These disturbance voltages can influence electronic

devices. The disturbance voltages cause by inductors

must be limited at the emission source by connecting

suppression circuits (diode or RC circuit). Only use

suppressors that are intended for use with your relay or

fan.

 Switching cubicle illumination

Use light bulbs for the switching cubicle illumination, e.g.

LINESTRA lamps. Avoid the use of luminescent lamps

because these produce noise fields. If you cannot avoid

using luminescent lamps, the measures described in

Figure 5-1 will be necessary.

5.1 Installation

5.1.1 Installation instructions

Electromagnetic compatibility

Electromagnetic compatibility involves all questions regarding electric, magnetic and

electromagnetic emission effects. To avoid disturbing influences on electrical installations,

these effects must be reduced to a minimum. The construction of device, correct connection

of bus lines and the suppression of self inductances are essential limitation measures. See

also the note in section 4.2.1 (protecting against lightni

ng strikes).

Suppression of self inductances

Figure 5-1 Measures to suppress

luminescent lamps in a

cubicle

Arrangement of devices and cables

 Maintaining clearance to reduce noise

A both simple and effective way of reducing disturbing influences is to maintain clearances

between the culprit and victim device or cable. Inductive and capacitive disturbances

decrease with the square of the distance between the elements involved. This means that

doubling the distance reduces the effect of the disturbance by a factor 4. If placement

considerations are taken into account in the planning of a building or a cubicle, these

measures can usually be implemented very cheaply.

5 Installation and Maintenance

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