Yamatake HGC303, User Manual

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Installation Yamatake Corporation
2-14 Model HGC303 - Heat Value Gas Chromatograph
2-4-2 : Fieldbus wiring
Signal wire
A Fieldbus signal is transmitted via 2-wire isolated signal lines.
Please keep in mind that the Fieldbus signal has polarity, positive (+) and negative (-).
All of the (+) terminals must be connected to each other and similarly, all of the (-) ter-
minals must be connected each other.
An important aspect of fieldbus is that neither of the signal wires are grounded.
Shielding
The preferred type of cable for fieldbus is a shielded cable.
Assemble a lugged shield wire connected to the metallized shield of each cable.
Connect all shield wires together to the terminal block.
In addition, connect the overall shield to the ground at one point in instruments room
to protect against field noise.
Do not ground the shield at multiple points.
Termination
A terminator shall be connected at both ends of the signal wire pair, at the field device
end and the host device end.
Connect the terminator between signal (+) and (-).
ONLY TWO terminators are needed per fieldbus segment.
Never connect a terminator between the signal (+ or -) and cable shield.
Figure 2-8 Example of cable finish
Heat shrink sleeve
Jacket
Overall shield
Shield wire
Wire terminal
Twiseted pair wire