Siemens 7MF4033 series, Руководство пользователя

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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 M
Ω
minimum
– Impedance if series connected ................Less than 10
Ω
– Impedance if parallel connected ......Greater than 50k
Ω
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 ..........................62.5k
Ω
– Maximum series impedance..................................160
Ω
– Minimum parallel impedance .............................3125
Ω