Practical Industrial Data Networks:Design, Installation and ...

208 Practical Industrial Data Networks: Design, Installation and TroubleshootingFoundation Fieldbus A(H )1To otherHSE linksHSESwitchHigh SpeedEthernet(HSE) LinkHSELinkDeviceFoundation Fieldbus B(H )1Foundation Fieldbus C(H )1Figure 14.6High-speed Ethernet and Foundation Fieldbus14.8 Good wiring and installation practice with Fieldbus14.8.1 Termination preparationIf care is taken in the preparation of the wiring, there will be fewer problems later andminimal maintenance required.A few points to be noted here are:• Strip 50 mm of the cable sheathing from the cable and remove the cablefoil.• Strip 6 mm of the insulation from the ends. Watch out to avoid wire nickingor cutting off strands of wire. Use a decent cable-stripping tool.• Crimp a ferrule on the wire ends and on the end of the shield wire. Crimpferrules are preferable as they provide a gas tight connection between thewire and the ferrule that is corrosion resistant. It is the same metal as theterminal in the wiring block.• An alternative strategy is to twist the wires together and to tin them withsolder. Wires can be put directly into the wire terminal but make sure allstrands are in and they are not touching each other. Make sure that thestrands are not stretched to breaking point.• Do not attach shield wires together in a field junction box. This can be thecause of ground loops.• Do not ground the shield in more than one place (inadvertently).• Use good wire strippers to avoid damaging the wire.14.8.2 Installation of the complete systemOther system components can be installed soon after the cable is installed. This includesthe terminators, power supply, power conditioners, spurs and in some cases, the intrinsicsafety barriers. Some devices already have terminator built-in. In that case, be careful thatyou are not doubling up with terminators.Check whether the grounding is correct. There should only be one point for the shieldground point.