Electromagnetic Interference (EMI) can be an intermittent condition. Improperly shielded installations can provide good control for a while and then cause problems. For this reason it is important to be sure all shields are properly installed.
All shielded cable must be twisted conductor pairs. Do not attempt to tin the
braided shield. All signal lines should be shielded to prevent picking up stray
signals from adjacent equipment. Connect the shields to the grounding lug on the
chassis plate below Terminal 9. Keep grounding connections under 2 inches (5
cm) length. A solid ground connection must be made from "earth" or ground to
the grounding lug to provide proper chassis grounding. Refer to local wiring
codes for proper grounding methods.
Wire exposed beyond the shield should be as short as possible, not exceeding 6
inches. The other end of the shields must be left open and insulated from any
other conductor. Do not run shielded signal wires with other wires carrying large
currents. See Woodward application note 50532, EMI Control for Electronic
Governing Systems, for more information.
Where shielded cable is required, cut the cable to the desired length and prepare
the cable as instructed below and shown in Figure 2-2.
Figure 2-2. Preparation of Shielded Cables
1. Strip outer insulation from both ends, exposing the braided or spiral
wrapped shield. Do not cut the shield on the control end. Cut off the shield
on the end away from the 2301A control.
2. Use a sharp, pointed tool to carefully spread the strands of the shield.
3. Pull the inner conductors out of the shield. Twist braided shields to prevent
fraying
