Chapter 7 Earthing and Shielding
GFK-2958E
RSTi-EP User Manual
331
If you wish to avoid the disadvantages associated with creating an earth loop with two-sided shields,
it is recommended you connect one side of the shield through a high impedance.
For longer lengths of shielded cables, such as if a sensor must be added to a control panel, a
potential difference between both end points must not be ignored.
However, such shield conductors are relatively expensive and also require more time in working with
them. Another possibility would be to place an additional voltage equalizing cable between the
measurement location and the control panel. The shield can then be hooked up on both sides.
A high-impedance earth connection is also another option. In the control panel, the shield is then
connected to the earth potential, and the shield has a high-impedance connection to earth at the
measurement location via a gas discharge tube. This solves the problem of a potential transfer and
50-Hz humming.
For non-isolated measurement locations, two gas discharge tubes must be installed. One connects
the shield to earth, and the other connects it to the non-isolated measurement location. This method
prevents a galvanic coupling between the measurement circuit and the earthed measurement
location.
Summary of Contents for GFK-2958E
Page 1: ...RSTi EP User Manual GFK 2958E November 2017 ...
Page 23: ...Chapter 1 Introduction GFK 2958E RSTi EP User Manual 19 Notes ...
Page 56: ...Chapter 3 Configuration GFK 2958E RSTi EP User Manual 52 Notes ...
Page 183: ...Chapter 5 Detailed Descriptions of I O Modules GFK 2958E RSTi EP User Manual 179 EP 5111 ...
Page 184: ...Chapter 5 Detailed Descriptions of I O Modules GFK 2958E RSTi EP User Manual 180 EP 5111 ...
Page 316: ...Chapter 5 Detailed Descriptions of I O Modules GFK 2958E RSTi EP User Manual 312 Notes ...
Page 330: ...Chapter 6 Installation GFK 2958E RSTi EP User Manual 326 Notes ...
Page 344: ...Chapter 7 Earthing and Shielding GFK 2958E RSTi EP User Manual 340 ...
Page 345: ...Chapter 7 Earthing and Shielding GFK 2958E RSTi EP User Manual 341 Notes ...
Page 385: ...Chapter 8 Web Server GFK 2958E RSTi EP User Manual 381 Notes ...
Page 401: ...Chapter 11 Disassembly and Disposal GFK 2958E RSTi EP User Manual 397 Notes ...
Page 413: ...Chapter 12 LED Indicators and Troubleshooting GFK 2958E RSTi EP User Manual 409 Notes ...
Page 416: ...Chapter 14Accessories and Replacement Parts GFK 2958E RSTi EP User Manual 412 Notes ...