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Installation UMSITRPDS3-1

November 2010

4-20

4.3.9 Connection of Miscellaneous Hardware

Miscellaneous non-signaling hardware (e.g., recorders, current meters) may be connected to a Point-to-

Point network in accordance with the following list.

IMPORTANT

No non-signaling hardware (meters or measuring devices) may be connected to a

Multi-Drop network since the transmitters, in this mode, do not output an analog

process variable.

• Miscellaneous hardware may be series or parallel connected to the network according to its function.

• Miscellaneous hardware must be passive two-terminal devices.

• Miscellaneous hardware may not generate any type of noise or signals, other than noise that is

inherent in resistive components.

• Individual miscellaneous hardware must meet the following requirements:

– Capacitance to ground..........................50 pF maximum

– Resistance to ground ............................1 MΩ minimum

– Impedance if series connected ................Less than 10Ω

– Impedance if parallel connected ......Greater than 50kΩ

The maximum number of miscellaneous devices per network is 16. The combined electrical

characteristics may not exceed the following:

– Maximum capacitance to ground........................800 pF

– Minimum resistance to ground ..........................62.5kΩ

– Maximum series impedance..................................160Ω

– Minimum parallel impedance .............................3125Ω

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Siemens SITRANS P Manual do Utilizador Página 72