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SIGNAL GROUNDING

To effectively ground a shield of a wire or cable carrying
signals, the shield must be intentionally connected to earth, or
to some conducting body serving in place of earth, through a
low impedance ground connection.

Wire or cable shields must be grounded at one end only to
eliminate circulating currents and resultant noise by
eliminating differences in potential between the two ends.

Shield drain wires must be as short as possible and insulated
from each other and other conducting objects, except at the
point of connection.  When connecting a shielded, twisted-pair
input to the C1900 terminal block, see Figure 4.1, ensure that
the extension of the shield from the cable jacket is as short as
possible – (preferably 25mm / 1.0in or less), and maintain the
twisted-pair configuration of the two wires up to the point of
termination.

Fig. 4.1 C1900 Terminal Block

Note. 

Thermocouples should always have their

shields grounded at the process end only, to avoid
charging currents.

If a double-shielded wire is used, ground the inner shield at
one end and ground the outer shield at the other end.

Summary of Contents for C1950

Page 1: ...DS C1900RC EN Quick Reference Guide C1900 recorders IM C1900 QR Quick Reference Guide C1900 recorder and recorder controller IM C1900 QC Search for or click on Installation Guide C1900 Circular chart recorder and recorder controller IM C1900 INS Operating Guide C1900 Circular chart recorder IM C1900 OGR Operating Guide C1900 Circular chart recorder controller IM C1900 OGC Programming Guide C1900 C...

Page 2: ...ced in full or part without prior approval of the Technical Publications Department Health and safety To ensure that our products are safe and without risk to health the following points must be noted The relevant sections of these instructions must be read carefully before proceeding Warning labels on containers and packages must be observed Installation operation maintenance and servicing must o...

Page 3: ...ined in this supplement such as shielding grounding and radio transmission exclusion zones Each of these practices should be considered routine in assuring and safeguarding public health and safety and in maintaining the integrity of electrical instrumentation Fig 1 1 C1900 Documentation 1 INTRODUCTION SPECIFICATION PROGRAMMING OPERATION INSTALLATION Part No IM C1900 CON CONTROLLER PACK SPECIFICAT...

Page 4: ... large degree how the electrical control systems will behave in the presence of EMI RFI emissions A shield is a metal construction of aluminium foil aluminium conductors mylar or copper conductors surrounding the interior of a wire or cable The shield helps to prevent interference or noise from entering the wire and helps to prevent signals from leaving the wire and interfering with adjacent wires...

Page 5: ...ible and insulated from each other and other conducting objects except at the point of connection When connecting a shielded twisted pair input to the C1900 terminal block see Figure 4 1 ensure that the extension of the shield from the cable jacket is as short as possible preferably 25mm 1 0in or less and maintain the twisted pair configuration of the two wires up to the point of termination Fig 4...

Page 6: ... the NRC 8dB de rating of the 10V m field strength limit The size of the exclusion zone s should be site specific and dependent upon the effective radiated power of the portable EMI RFI emitter type s likely to be used Exclusion Zone Some examples of exclusion zone distances recognized by European Industry standards for CE marking and by the U S Nuclear Regulatory Commission NRC are shown in Figur...

Page 7: ...Sales Software Service ...

Page 8: ...l rights in this document and in the subject matter and illustrations contained therein Any reproduction disclosure to third parties or utilization of its contents in whole or in parts is forbidden without prior written consent of ABB ABB 2018 ABB Limited Measurement Analytics Howard Road St Neots Cambridgeshire PE19 8EU UK Tel 44 0 870 600 6122 Fax 44 0 1480 217 948 Email enquiries mp uk gb abb c...

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