Red-lion PCU Manuel d'utilisateur télécharger pdf (Page 15)

EMC INSTALLATION GUIDELINES

Although this unit is designed with a high degree of immunity to

ElectroMagnetic Interference (EMI), proper installation and wiring methods

must be followed to ensure compatibility in each application. The type of

electrical noise, source or coupling method into the unit may be different for

various installations. In extremely high EMI environments, additional

measures may be needed. The unit becomes more immune to EMI with fewer

I/O connections. Cable length, routing and shield termination are very

importantand can mean the differencebetween a successful or a troublesome

installation. Listed below are some EMC guidelines for successful

installation in an industrial environment.

1. The unit should be mounted in a metal enclosure, which is properly

connected to protective earth.

2.Useshielded(screened) cables forallSignaland Control inputs.Theshield

(screen) pigtail connection should be made as short as possible. The

connection point for the shield depends somewhat upon the application.

Listed below are the recommended methods of connecting the shield, in

order of their effectiveness.

a. Connect the shield only at the panel where the unit is mounted to earth

ground (protective earth).

b. Connect the shield to earth ground at both ends of the cable, usually

when the noise source frequency is above 1 MHz.

c. Connect the shield to common of the unit and leave the other end of the

shield unconnected and insulated from earth ground.

3.Never run Signal or Control cables inthe sameconduit orraceway with AC

power lines, conductors feeding motors, solenoids, SCR controls, and

heaters, etc. The cables should be run in metal conduit that is properly

grounded. This is especially useful in applications where cable runs are

long and portable two-way radios are used in close proximity or if the

installation is near a commercial radio transmitter.

4.SignalorControlcableswithinanenclosureshouldberoutedasfarawayas

possible from contactors, control relays, transformers, and other noisy

components.

5. In extremely high EMI environments, the use of external EMI suppression

devices, such as ferrite suppression cores, is effective. Install them on

Signal and Control cables as close to the unit as possible. Loop the cable

through the core several times or use multiple cores on each cable for

additionalprotection.Installlinefilterson the power inputcabletotheunit

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Figure 6, Hardware

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Red-lion PCU Manuel d'utilisateur Page 15