Type DH7091 Transient Protection Assembly

Transcription

1 Type DH7091 Transient Protection Assembly D3P Installation Manual PN4.10:DH7091 Revision A June 1991 This manual supersedes the previous issue dated February In October 2001, company logos and documentation references were updated in this manual, but no technical changes were made.

2 PROVOX is a mark of one of the Emerson Process Management group of companies. All other marks are the property of their respective owners. 1991, 2001 Fisher-Rosemount Systems, Inc. All rights reserved. PrintedinUSA The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to modify or improve the designs or specifications of such products at any time without notice.

3 Type DH7091 Transient Protection Assembly (Revision A June 1991) Contents iii Contents 1 Introduction Cautions and Notes Answers for Your Questions Product Description Physical Installation Electrical Installation... 4 Figures Figure 1. Type DH7091 Transient Protection Assembly and User Supplied Mounting Plate... 5 Figure 2. Eight Cabinet Grouping (Distributed Control System Grounding)... 6 Figure 3. Two to Seven Cabinet Grouping (DC/Cabinet Grounding System)... 7 Figure 4. Single Cabinet (DC Cabinet Grounding System). 7 Figure 5. Multiple Cabinet System Grounding... 8 Figure 6. Multiple Cabinet System Grounding Showing Mount Placement of Transient Protection Assembly... 9 Tables Table 1. Related Documents... 1

4 iv Contents Type DH7091 Transient Protection Assembly (Revision A June 1991) Blank page.

5 1 Figure 1-Table 1 1 Introduction This installation manual describes the physical and electrical installation requirements for the Type DH7091 Transient Protection Assembly. The transient protection assembly provides a ground path for transient high voltages induced in inter-building coaxial cables by lightning and other sources. PROVOXr Process Management Systems use coaxial cable in lengths as long as 7500 feet (2288 m) for data highways and control I/O card file to controller connections. Refer to Installation Planning Manual PN1:007, Lightning Protection Guidelines for Instrumentation Systems, for a detailed description of lightning protection principles, inspection and maintenance guidelines for protection systems, and lightning protection planning considerations. Table 1 lists documents related to this assembly and its installation. Table 1 Related Documents PN1:003 AC and DC Power & Ground Wiring PN1:004 Signal Wiring and Data Highway Guidelines PN1:007 Lightning Protection Guidelines for Instrumentation Systems 2 Cautions and Notes Cautions and Notes attract attention to essential or critical information in this manual. The types of information included in each are explained in the following: Caution... All cautions have this form and symbol. Do not disregard cautions. They are installation, operation, or maintenance procedures, practices, conditions, statements, and so forth, which if not strictly observed, may result in damage to, or destruction of, equipment or may cause a long term health hazard.

6 2 Note... Notes have this form and symbol. Notes contain installation, operation, or maintenance procedures, practices, conditions, statements, and so forth, that alert you to important information which may make your task easier or increase your understanding. 3 Answers for Your Questions If you believe that this product is not performing as expected, or if you have comments about this manual, please contact your Emerson Process Management representative or sales office. You may also complete and send in the Reader Evaluation Form located in the front of this manual. We also appreciate your suggestions on ways to improve any page of the manual. Please mark your suggestions on a copy of the page and include it with the evaluation form. Thank you for providing this information. 4 Product Description The Type DH7091 Transient Protection Assembly is a passive device inserted in series on the PROVOX Data Highway to assist in isolating damage caused by transient voltages surges. The assembly minimizes equipment damage and personal injury by grounding transient voltages above 12 volts. Each assembly has the following characteristics: J J J J Inductance 10 uh Capacitance 100 pf Resistance 1 ohm Transient current 2500 A Max

7 3 Each assembly includes: J J J Transorb (avalanche diode), to ground induced transient spikes from 12 to 30 volts Gas discharge tube, to ground induced transient spikes over 30 volts Two female BNC connectors (labeled LINE and EQUIP) Note... No more than 12 transient protection Assemblies should be used within a 7500 foot (2286 m) cable run. 5 Physical Installation Note... Use two Type DH7091 Transient Protection Assemblies for each inter-building cable (one at each building cable entrance). Figure 1 shows the outline dimensions for the transient protection assembly and user supplied mounting plate. Aluminum is the recommended material for fabrication of the mounting plate. Use these dimensions to identify and prepare the desired mounting location. Mount the assemblies as close to the cabinet ground cable as possible. Note... To ensure adequate ground connection, the transient protection assembly must be properly bonded to the PROVOX system cabinet or PIG. Position each assembly in the desired mounting location and secure with user supplied hardware. Figure 2 thru 6 provide some examples of assembly mounting for typical layouts.

8 4 Install a steel conduit between buildings to house the cable run. Ground the conduit at both ends and to pipe racks between conduit sections. This provides both mechanical and electrical protection for cables. Run the conduit above or below ground. When possible, use the above ground method to utilize the insulation provided by air. Below ground installation is more susceptible to lightning-induced voltages caused by earth step potentials. Use a transient protection assembly at the cable entry/exit for each building. Caution... DO NOT route primary and secondary data highway cables in the same conduit or within 6 inches (152 mm) of each other. Cables routed too close together when using transient protection assemblies can cause cross-coupling of data signals which may interfere with the proper operation of the instrumentation system. 6 Electrical Installation Note... Improper grounding of the transient protection assembly prevents proper operation. Use the guidelines in Installation Planning Notes PN1:003, AC and DC Power & Ground Wiring, and PN1:007, Lightning Protection Guidelines for Instrumentation Systems. After physical installation is complete, connect the cable from the PROVOX Instrumentation System to the BNC connector labeled EQUIP on each transient protection assembly. Prepare an appropriate length of cable to connect between buildings. Use DH7080-Series Data Highway products to construct the cable. Run the cable between the buildings through the conduit. Connect each end of the cable to the LINE BNC connector on a transient protection assembly.

9 5 1.4 (35.6) LINE EQUIP Mounting Plate Top View (Mounted) 2.25 (57.2) 1.2 (30.5) 3.25 (82.6) Side View INCH (mm) 2.94 (74.7) (3.9) Typ 4 places 1.1 (27.9) 2.25 (57.2) (11.4) DIA Hole 3.25 (82.6) 1.15 (20.2) Plate Views X00549:DH Figure 1. Type DH7091 Transient Protection Assembly and User Supplied Mounting Plate

10 6 Line Neutral Ground 1 Grounded Steel Column 2 PROVOX Instrument Ground 3 DC Ground Cabinet Ground MGB SeeFigure6 Plant Ground Notes: 1 Conductor used to connect the grounding electrode to the NEUTRAL Ground bond at the source of a separately derived instrumentation power system.(per NEC 250.6)(CSA22.1 Section 10) 2 Supplemental conductor used to connect the grounding electrode for the source of a separately derived instrumentation Power System, directly to the Plant Ground Grid System. This is used to provide low impedance ground reference for EMI/RFI high frequency noise.( Per NEC /250.83) (CSA 22.1 Section 10) Figure 2. 3 The conductor used to provide a low impedance ground reference for the DC Power System(Logic, Transmitter, Output) and/or a Cabinet Ground for EMI/ RFI high frequency noise protection of the instrumentation cabinets, file and wiring sheilds. Eight Cabinet Grouping (Distributed Control System Grounding)

11 7 Power Bus PROVOX Data Highway Power Bus LGB To PROVOX Instrument Ground (PIG) Figure 3. Cabinet Ground Straps SeeFigure6 Legend SC PSC Two to Seven Cabinet Grouping (DC/Cabinet Grounding System) X00551:DH Power Bus SC PSC PROVOX Instrument Ground (PIG) SeeFigure6 Figure 4. X00552:DH Single Cabinet (DC Cabinet Grounding System)

12 8 PROVOX Data Highway System Cabinet System Cabinet System Cabinet System Cabinet LGB LGB LGB LGB DC MGB CAB. MGB Notes: A LGB will be required for each cabinet grouping of 8 or less. A cabinet ground will be required for each grouping of 8 or more. Figure 5. To PIG Multiple Cabinet System Grounding MGB GROUND WIRE SIZING CHART Up to 25 feet Up to 50 feet Up to 200 feet 1/0 AWG 2/0 AWG 4/0 AWG Recommend using PRESTOFLEX Welding Cable X00553:DH7091-0

13 9 PROVOX Data Highway System Cabinet System Cabinet System Cabinet System Cabinet LGB LGB LGB LGB DC MGB CAB. MGB Notes: A LGB will be required for each cabinet grouping of 8 or less. To PIG MGB Transient Protection Assemblies Cabinet Ground Cable Figure 6. Solid Copper Bar X00554:DH Multiple Cabinet System Grounding Showing Mount Placement of Transient Protection Assembly

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15 11 Notes

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18 PN4.10:DH7091