15
FM Certification
Safety
Terminators
At each end of the trunk cable an approved line terminator with the following
parameters is suitable:
R = 90 to 100 Ω
C = 0 to 2.2 μF
The resistor must be infallible according to IEC 60079-11. One of the two allowed
terminators might already be integrated in the associated apparatus (bus supply unit).
System Evaluation
The number of passive devices like transmitters, actuators, hand held terminals
connected to a single bus segment is not limited due to I.S. reasons. Furthermore, if the
above rules are respected, the inductance and capacitance of the cable need not to be
considered and will not impair the intrinsic safety of the installation.
Figure 3 Passive Devices
Note 5. Maintenance and Repair
The instrument modification or parts replacement by other than authorized
representative of GE Masoneilan is prohibited and will void Factory Mutual Intrinsically
Safe and Non-incendive Approval.
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