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EI Nexus 1250 Installation & Operation Manual

Advanced performance power meter and power quality recorder
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Nexus
®
1250/1252
Advanced performance power meter
and power quality recorder
Installation & Operation Manual
Version 1.29
August 7, 2008
Doc # E107706 V.1.29
E
Electro Industries/GaugeTech
1800 Shames Drive
Westbury, New York 11590
Tel: 516-334-0870
Fax: 516-338-4741
Sales@electroind.com
www.electroind.com
"The Leader in Power Monitoring and Control"

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  • Page 1 Nexus ® 1250/1252 Advanced performance power meter and power quality recorder Installation & Operation Manual Version 1.29 August 7, 2008 Doc # E107706 V.1.29 Electro Industries/GaugeTech 1800 Shames Drive Westbury, New York 11590 Tel: 516-334-0870 Fax: 516-338-4741 Sales@electroind.com www.electroind.com “The Leader in Power Monitoring and Control”...
  • Page 2 Electro Industries/GaugeTech Doc #E107706...
  • Page 3 Nexus® 1250/1252 Meter Installation and Operation Manual Revision 1.29 Published by: Electro Industries/GaugeTech 1800 Shames Drive Westbury, NY 11590 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or information storage or retrieval systems or any future forms of...
  • Page 4 Customer Service and Support Customer support is available 9:00 am to 4:30 pm, Eastern Standard Time, Monday through Friday. Please have the model, serial number and a detailed problem description available. If the problem concerns a particular reading, please have all meter readings available. When returning any merchandise to EIG, a return materials authorization number is required.
  • Page 5 About Electro Industries/GaugeTech Electro Industries/GaugeTech was founded in 1973 by Dr. Samuel Kagan. Dr. Kagan’s first innovation, an affordable, easy-to-use AC power meter, revolutionized the power-monitoring field. In the 1980s Dr. Kagan and his team at EIG developed a digital multifunction monitor capable of measuring every aspect of power.
  • Page 6 Electro Industries/GaugeTech Doc # E107706...

  • Page 7: Table Of Contents

    Table of Contents Chapter 1: Three-Phase Power Measurement 1.1: Three-Phase System Configurations 1.1.1: Wye Connnection 1.1.2: Delta Connection 1.1.3: Blondell’s Theorem and Three Phase Measurement 1.2: Power, Energy and Demand 1.3: Reactive Energy and Power Factor 1.4: Harmonic Distortion 1-10 1.5: Power Quality 1-13 Chapter 2: Nexus®...
  • Page 8 5.7: RS485 Connection - Nexus® Meter to an RS485 Master 5.7.1: Using the Unicom 2500 5.8: RS485 Connection - Nexus® Meter to P40N External Display 5-11 5.9: RS485 Connection - Nexus® Meter to P60N External Display 5-12 5.10: Communication Ports on the Nexus® Output Modules 5-13 5.11: RS485 Connection - Nexus®...
  • Page 9 9.5: Analog Transducer Signal Output Modules 9.5.1: Overview 9.5.2: Normal Mode 9.6: Digital Dry Contact Relay Output Module (Form C) 9.6.1: Overview 9.6.2: Communication 9-10 9.6.3: Normal Mode 9-10 9.7: Digital Solid State Pulse Output (KYZ) Module 9-11 9.7.1: Overview 9-11 9.7.2: Communication 9-12...
  • Page 10 viii Electro Industries/GaugeTech Doc # E107706...

  • Page 11: Chapter 1: Three-Phase Power Measurement

    Chapter 1 Three-Phase Power Measurement This introduction to three-phase power and power measurement is intended to provide only a brief overview of the subject. The professional meter engineer or meter technician should refer to more advanced documents such as the EEI Handbook for Electricity Metering and the application standards for more in-depth and technical coverage of the subject.
  • Page 12 Fig 1.2: Phasor Diagram Showing Three-phase Voltages and Currents The phasor diagram shows the 120 angular separation between the phase voltages. The phase-to-phase voltage in a balanced three-phase Wye system is 1.732 times the phase-to- neutral voltage. The center point of the Wye is tied together and is typically grounded. Table 1.1 shows the common voltages used in the United States for Wye-connected systems.

  • Page 13: 2: Delta Connection

    1.1.2: Delta Connection Delta connected services may be fed with either three wires or four wires. In a three- phase Delta service, the load windings are connected from phase-to-phase rather than from phase-to-ground. Figure 1.3 shows the physical load connections for a Delta service.

  • Page 14: 3: Blondell's Theorem And Three Phase Measurement

    Fig 1.5: Phasor Diagram Showing Three-phase, Four-wire Delta Connected System 1.1.3: Blondell’s Theorem and Three Phase Measurement In 1893 an engineer and mathematician named Andre E. Blondell set forth the first scientific basis for poly phase metering. His theorem states: If energy is supplied to any system of conductors through N wires, the total power in the system is given by the algebraic sum of the readings of N Wattmeters so arranged that each of the N wires contains one current coil, the corresponding potential coil being...
  • Page 15 Some digital meters calculate the individual phase power values one phase at a time. This means the meter samples the voltage and current on one phase and calculates a power value. Then it samples the second phase and calculates the power for the second phase. Finally, it samples the third phase and calculates that phase power.

  • Page 16: Power, Energy And Demand

    1.2: Power, Energy and Demand It is quite common to exchange power, energy and demand without differentiating between the three. Because this practice can lead to confusion, the differences between these three measurements will be discussed. Power is an instantaneous reading. The power reading provided by a meter is the present flow of Watts.
  • Page 17 Time Interval Accumulated (Minute) Power (kW) Energy (kW) Energy (kWh) 0.50 0.50 0.83 1.33 0.67 2.00 0.92 2.92 1.00 3.92 1.00 4.92 1.17 6.09 1.17 7.26 1.00 8.26 1.17 9.43 1.33 10.76 0.83 12.42 0.83 12.42 1.17 13.59 1.33 14.92 Table 1.2: Power and Energy Relationship Over Time As in Table 1.2, the accumulated energy for the power load profile of Figure 1.7 is 14.92 kWh.

  • Page 18: Reactive Energy And Power Factor

    Kilowatt-hours Intervals Figure 1.8: Energy Use and Demand As can be seen from this example, it is important to recognize the relationships between power, energy and demand in order to control loads effectively or to monitor use correctly. 1.3: Reactive Energy and Power Factor The real power and energy measurements discussed in the previous section relate to the quantities that are most used in electrical systems.
  • Page 19 The voltage (V) and the total current (I) can be combined to calculate the apparent power or VA. The voltage and the in-phase current (IR) are combined to produce the real power or watts. The voltage and the quadrature current (IX) are combined to calculate the reactive power.

  • Page 20: Harmonic Distortion

    1.4: Harmonic Distortion Harmonic distortion is primarily the result of high concentrations of non-linear loads. Devices such as computer power supplies, variable speed drives and fluorescent light ballasts make current demands that do not match the sinusoidal waveform of AC electricity. As a result, the current waveform feeding these loads is periodic but not sinusoidal.
  • Page 21 Expanded Harmonic Currents -100 -150 -200 -250 2 Harmonic Current 3 Harmonic Current 5 Harmonic Current 7 Harmonic Current A Current Total Hrm Figure 1.12: Waveforms of the Harmonics The waveforms shown in Figure 1.12 are not smoothed but do provide an indication of the impact of combining multiple harmonic frequencies together.

  • Page 22: Power Quality

    However, when monitors can be connected directly to the measured circuit (such as direct connection to 480 volt bus) the user may often see higher order harmonic distortion. An important rule in any harmonics study is to evaluate the type of equipment and connections before drawing a conclusion.
  • Page 23 It is often assumed that power quality problems originate with the utility. While it is true that many power quality problems can originate with the utility system, many problems originate with customer equipment. Customer-caused problems may manifest themselves inside the customer location or they may be transported by the utility system to another adjacent customer.
  • Page 24 Electro Industries/GaugeTech 1-14 Doc #E107706...

  • Page 25: Meter Features

    Chapter 2 Nexus® 1250 1252 Meter Overview 2.1: Meter Features Electro Industries’ Nexus® 1250/1252 meter is the latest in a generation of meters that combine high-end revenue metering with sophisticated power quality analysis. Features of the Nexus® 1250/1252 meter include: •...
  • Page 26 RS485 Computer or SCADA System Expandable Output Modules Nexus ® Display Modem/Ethernet Option RJ-11 or RJ-45 Connection Nexus 1250 1252 Meter ® ® Figure 2.1: The Nexus Metering System The Nexus® 1250/1252 meter’s Revenue Metering capabilities include: • Delivers laboratory-grade 0.04% Watt-hour accuracy in a field-mounted device. •...

  • Page 27: Upgrading The Meter's V-Switch ™ Key

    • Measures Flicker. • Offers EN50160 logging and analysis. Nexus® 1250/1252 Meter Memory, Communication, and Control capabilities include: Up to 4 Meg NVRAM. • • 4 High Speed Communication Ports. • Multiple Protocols (see section below on DNP V3.00). • 90msec High Speed Updates for Control.

  • Page 28: Dnp V3.00 Level

    2.3: DNP V3.00 Level 1 and Level 2 The Nexus® 1250 meter supports DNP V300 Level 1; the Nexus® 1252 meter supports DNP V3.00 Level 2. DNP Level 2 Features include: • Up to 136 measurements (64 Binary Inputs, 8 Binary Counters, 64 Analog Inputs) can be mapped to DNP Static Points (over 3000) in the customizable DNP Point Map.

  • Page 29: Measurements And Calculations

    2.6: Measurements and Calculations The Nexus® 1250/1252 meter measures many different power parameters. Following is a list of the for- mulas used to conduct calculations with samples for Wye and Delta services. Samples for Wye: v an , v bn , v cn , i a , i b , i c , i n Samples for Delta: v ab , v bc , v ca , i a , i b , i c Root Mean Square (RMS) of Phase to Neutral Voltages: n = number of samples For Wye: x = an, bn, cn...
  • Page 30 Power (Watts) per phase: For Wye: x = a, b, c ∑ • Apparent Power (VA) per phase: For Wye: x = a, b, c • Reactive Power (VAR) per phase: For Wye: x = a, b, c − Watt Power (Watts) Total: For Wye: For Delta:...
  • Page 31 Reactive Power (VAR) Total: For Wye: For Delta: ⎡ ⎤ ∑ • ⎢ ⎥ ⎢ ⎥ • − ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ ⎡ ⎤ ∑ • ⎢ ⎥ ⎢ ⎥ • − ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ Apparent Power (VA) Total: For Wye: For Delta:...
  • Page 32 Phase Angles: ∠ − % Total Harmonic Distortion (%THD): For Wye: x = V AN , V BN , V CN , I A , I B , I C For Delta: x = I A , I B , I C , V AB , V BC , V CA ∑...

  • Page 33: Demand Integrators

    2.7: Demand Integrators Power utilities take into account both energy consumption and peak demand when billing customers. Peak demand, expressed in kilowatts (kW), is the highest level of demand recorded during a set period of time, called the interval. The Nexus® 1250/1252 meter supports the following most popular conventions for averaging demand and peak demand: Thermal Demand, Block Window Demand, Rolling Window Demand and Predictive Window Demand.
  • Page 34 Example: Using the previous settings of 3 five-minute intervals and a new setting of 120% prediction factor, the working of the Predictive Window Demand could be described as follows: At 12:10, we have the average of the subintervals from 11:55-12:00, 12:00-12:05 and 12:05-12:10. In five minutes (12:15), we will have an average of the subintervals 12:00-12:05 and 12:05-12:10 (which we know) and 12:10-12:15 (which we do not yet know).

  • Page 35: Nexus® External Output Modules

    2.8: Nexus External Output Modules (Optional) ® The following multiple analog or digital Output modules mount externally to the Nexus® meter. The meter supports up to four Output modules using internal power. Use the additional power supply, EIG PSIO, to extend Output capability. See Section 3.4 for mounting diagrams. See Chapter 9 for details on installation and usage of the Nexus®...

  • Page 36: Meter Specifications

    2.9: Meter Specifications UL Measurement Category - CategoryIII Rated Altitude - 2,000 Meters Maximum Specification Nexus® 1250/1252 Meter Option D: 24VDC (-20%) - 48VDC (+20%) Control Power Requirement Option D2: 120V AC/DC (-20%) - 230VAC (+20%) Connection Screws’ Torque: (6 to 9) in-lb. max. or (0.68 to 1) Nm max.

  • Page 37: Nexus® P40N, P41N, P43N Led External Display Specifications

    2.10: Nexus P40N, P41N, P43N LED External Display Specifications ® ® Specification Nexus P40N, P41N, P43N LED External Display Maximum Input Voltage 30V DC Minimum Input Voltage 7V DC Maximum Power Consumption 8 Watts Nominal Power Consumption Approximately 6 Watts Operating Temperature Range -40°C to + 80°C / -40°F to +176°F Overall Dimensions (HxWxL)
  • Page 38 Electro Industries/GaugeTech 2-14 Doc #: E107706...

  • Page 39: Chapter 3: Hardware Installation

    Chapter 3 Hardware Installation ® 3.1: Mounting the Nexus Meter The Nexus® 1250/1252 meter is designed to mount against any firm, flat surface. Use a #10 screw in each of the four slots on the flange to ensure that the unit is installed securely. For safety reasons, mount the meter in an enclosed and protected environment, such as in a switchgear cabinet.
  • Page 40 2.35” (5.96 cm) 3.40” (8.63 cm) MAX Figure 3.2: Nexus® 1250/1252 Meter Mounting Diagram, Side View Electro Industries/GaugeTech Doc #E107706...
  • Page 41 ® 3.2: Mounting the Nexus LED External Displays The Nexus® 1250/1252 meter LED Displays: Models # P40N, P41N and P43N, mount using a standard ANSI C39.1 drill plan. Secure the four mounting studs to the back of the panel with the supplied nuts. Six feet of RS-485 communication/power cable harness is supplied.

  • Page 42: Mounting The Nexus® P60N Touch Screen External Display

    ® 3.3: Mounting the Nexus P60N Touch Screen External Display Figure 3.4: Nexus® P60N Touch Screen Display Mounting Diagram The Nexus® P60N Touch Screen Display mounts easily, using the diagrams above and on the next page. A bezel and a gasket are included with the P60N. Since the P60N employs an LCD display, the viewing angle must be considered when mounting.
  • Page 43 Figure 3.6: Cutout for Nexus® P60N Touch Screen Display To bezel mount the P60N, cut an opening in the mounting panel. Follow cutout dimensions shown above. Carefully “drop in” the P60N with bezel and gasket attached. Fasten the unit securely with the four 6-32 hex nuts supplied. Electro Industries/GaugeTech Doc #E107706...

  • Page 44: Mounting The Nexus® External Output Modules

    ® 3.4: Mounting the Nexus External Output Modules Secure the mounting brackets to the Output module using the screws supplied (#440 pan-head screws). Next, secure the brackets to a flat surface using a #8 screw with a lock washer. If multiple Output modules are connected together, as shown in Figure 3.7, secure a mounting bracket to both ends of the group.
  • Page 45 Mounting Bracket (MBIO) Mounting Bracket (MBIO) 1.25” (3.175 cm) + Y Per Module 2.20” 3.43” (5.58cm) (8.712cm) 2 x 1.10” (2.79cm) .605” (1.53cm) 1.25” (3.175cm) Per Module Figure 3.9: Nexus® Output Modules Mounting Diagram, Front View Electro Industries/GaugeTech Doc #E107706...
  • Page 46 Electro Industries/GaugeTech Doc #E107706...

  • Page 47: Chapter 4: Electrical Installation

    Chapter 4 Electrical Installation 4.1: Considerations When Installing Meters Installation of the Nexus® 1250/1252 meter must be performed only by qualified personnel who follow standard safety precautions during all procedures. Those personnel should have appropriate training and experience with high voltage devices. Appropriate safety gloves, safety glasses and protective clothing are recommended.

  • Page 48: Wiring The Monitored Inputs And Voltages

    4.2: Wiring the Monitored Inputs and Voltages Select a wiring diagram from Section 4.8 that best suits your application. Wire the Nexus® 1250/1252 meter exactly as shown. For proper operation, the voltage connection must be maintained and must correspond to the correct terminal. Program the CT and PT Ratios in the Device Profile section of the Communicator EXT software;...

  • Page 49: Isolating A Ct Connection Reversal

    EIG Recommendations CT Size (VA) Maximum distance from CT to Nexus 1250/1252 Meter (Feet) ® WARNING! DO NOT leave the secondary of the CT open when primary current is flowing. This may cause high voltage, which will overheat the CT. If the CT is not connected, provide a shorting block on the secondary of the CT.

  • Page 50: Wiring Diagrams

    Control Power Option Suffix 18-60 Volts DC 90-276 Volts AC/DC Do not ground the unit through the negative of the DC supply. Separate grounding is required. Externally fuse the power supply with a 5 Amp @250V rated slow blow fuse. EIG recommends that you fuse both the L+ and N- connections for increased safety, but if you are fusing only one connection, fuse the L+ connection.
  • Page 51 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.1: 4-Wire Wye, 3-Element Direct Voltage with 4 CTs Electro Industries/GaugeTech Doc #E107706...
  • Page 52 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.2: 4-Wire Wye, 3-Element with 3 PTs and 4 CTs Electro Industries/GaugeTech Doc #E107706...
  • Page 53 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.3: 4-Wire Wye, 3-Element with 3 PTs and 3 CTs Electro Industries/GaugeTech Doc #E107706...
  • Page 54 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.4: 3-Wire, 2-Element Open Delta with 2 PTs and 3 CTs Electro Industries/GaugeTech Doc #E107706...
  • Page 55 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.5: 3-Wire, 2-Element Open Delta with 2 PTs and 2 CTs Electro Industries/GaugeTech Doc #E107706...
  • Page 56 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.6: 3-Wire, 2-Element Delta Direct Voltage with 3 CTs Electro Industries/GaugeTech 4-10 Doc #E107706...
  • Page 57 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.7: 3-Phase, 4-Wire, 2.5 Element with 2 PTs and 3 CTs Electro Industries/GaugeTech 4-11 Doc #E107706...
  • Page 58 NEXUS® Meter 0.25A SUPPLY POWER INPUT (Dependent on Equipped Power Supply Option) Figure 4.8: 4-Wire, 3-Element Grounded Delta with 4 CTs – G Option Electro Industries/GaugeTech 4-12 Doc #E107706...

  • Page 59: Chapter 5: Communication Wiring

    Chapter 5 Communication Wiring 5.1: Communication Overview RS232 communication is used to connect a single Nexus® 1250/1252 meter with another device, such as a computer, RTU or PLC. The link is viable for a distance of up to 50 feet (15.2 m) and is available only through the meter’s Port 1.
  • Page 60 RJ-11 Telephone Line allows a Nexus® 1250/1252 meter with the Internal Modem Option (INP2) to communicate with a PC. No other hardware is necessary for this easy-to-use connection. For more details, see Chapter 10 of this manual. RJ-11 NEXUS ® 1250/1252 Meter Originate Modem (or Internal to PC) Figure 5.2: RJ-11 Communication with Internal Modem Option...

  • Page 61: Network Connection

    RJ-45 Network Connection allows a Nexus® 1250/1252 meter with the Internal Network Option (INP200) to communicate with multiple PC’s simultaneously. No other hardware is necessary for this easy-to-use connection. For more details, see Chapter 11 of this manual. 10/100BaseT RJ-45 MODBUS/TCP over Ethernet NEXUS ®...
  • Page 62 For all communications: S=Shield. This connection is Output Modules and ® RS232 Extension Display require power used to reference the Nexus meter’s port to the Cable connections to the +/- same potential as the source. It is not an earth- (1 to 1 wiring) voltage terminals (dashed ground connection.

  • Page 63: Rs232 Connection-Nexus ® Meter To A Computer

    5.2: RS232 Connection—Nexus Meter to a Computer ® Use Port 1 for RS232 communication. Set the selector switch beneath the port to RS232. Insert one end of an RS232 extension cable into the Nexus® 1250/1252 meter’s 9-pin female serial port. Insert the opposite end into a port on the computer. The RS232 standard limits the cable length to 50 feet (15.2m).
  • Page 64 RS485 communication allows multiple devices to communicate on a bus. The Nexus® 1250/1252 meter’s Ports 1 to 4 are RS485 terminals, viable for a distance of up to 4000 feet (1219 m). (Port 1 can be switched between RS232 and RS485.) Below is a detail of a 2-wire RS485 port. 2-Wire RS485 Port Shield Twisted...
  • Page 65 Incorrect Connection: “T” “Tee” Connection Incorrect! The three wires connected in a “T” shape on both the (+) and (-) terminals will cause interfer- ence problems. RS485 Port Incorrect Connection: “Star” “Star” Connection Incorrect! The three wires connected in a “Star”...
  • Page 66 5.4: RS485 Connection—Nexus Meter to a Computer or PLC ® Use any Port on the Nexus® 1250/1252 meter. If you use Port 1, set the selector switch beneath the port to RS485 (see Figure 5.5). The link using RS485 is viable for up to 4000 feet (1219 meters). You must use an RS485 to RS232 converter, such as EIG’s Unicom 2500.
  • Page 67 5.7: RS485 Connection—Nexus Meter to an RS485 Master (Unicom or ® Modem Manager) To establish communication between a Nexus® 1250/1252 meter and any RS485 master, such as EIG’s Unicom 2500, Modem Manager or other RS232/RS485 converter, use a shielded, twisted pair cable.
  • Page 68 Figure 5.8: Unicom 2500 with Connections Figure 5.9: Detail of “Jumpers” The Unicom 2500 can be configured for either 4-wire or 2-wire RS485 connections. Since the Nexus® meter uses a 2-wire connection, you need to add jumper wires to convert the Unicom 2500 to the 2-wire configuration.
  • Page 69 5.8: RS485 Connection—Nexus Meter to the Nexus P40N External ® ® Display Insert one end of the supplied RS485 cable into Port 3 of the Nexus® 1250/1252 meter. Port 3 is factory-set to match the Nexus® display’s baud rate of 9600. To use a port other than Port 3, you must set the port’s baud rate to 9600 using the Communicator EXT software (see Chapter 3 of the Communicator EXT User Manual for instructions).
  • Page 70 5.9: RS485 Connection—Nexus Meter to the Nexus P60N External ® ® Display To connect the Nexus® P60N Touch Screen External Display, use the Stand Alone Interface Cable provided with the display. The cable is six (6) feet long with 20 AWG conductors (see detailed figure, below).
  • Page 71 5.10: Communication Ports on the Nexus Output Modules ® Female RS485 Side Port: use to connect to another module’s female RS485 side port. Male RS485 Side Port: use to connect to the Nexus® meter’s Port 4 (see Section 5.8) or to connect to another module’s male RS485 side port.
  • Page 72 5.11: RS485 Connection—Nexus Meter to Nexus Output Modules ® ® Six feet of RS485 cable harness is supplied. Insert one end of the cable into Port 4 of the Nexus® 1250/1252 meter. Insert the other end of the cable into the Output module’s female RS485 side port (see Figure 5.9). (The connectors fit only one way into the ports.) Use the male RS485 side port to attach another Output module.

  • Page 73: Steps To Determine Power Needed

    5.12: Steps to Determine Power Needed Available power for all ports of the Nexus® 1250/1252 meter is 12 VA. 1. Refer to the table below to determine the VA Ratings for Output modules and displays. 2. Add together the VA Ratings for Output modules and displays in use. 3.
  • Page 74 5.14: Linking Multiple Nexus Meters in Series ® You may connect a total of 31 Nexus® meters in series on a single bus using RS485. The cable length may not exceed 4000 feet (1219 meters). Before assembling the bus, each Nexus® meter must be assigned a unique address.
  • Page 75 You can use an RS485 repeater to network several links of instruments. NOTES: A maximum number of 31 Nexus® meters may be connected to one repeater. A maximum number of 31 repeaters may be included on the same network. ® Maximum 31 Nexus meters, RS485 Maximum 31...

  • Page 76: Remote Communication Overview

    5.15: Remote Communication Overview Either RJ-11 (INP2 Option) or RJ-45 (INP200 Option) can connect devices at great distances. Section 5.1 gives an overview of these communication options. Chapter 10 explains the INP2 Internal Modem Option; Chapter 11 explains the INP200 Network Option. You can use also use modems to connect devices.
  • Page 77 5.16: Remote Communication—RS232 NOTE: EIG recommends using RS485 wiring with a Modem Manager. See Section 5.17. For RS232 communication, use Port 1. Set the selector switch under the port to RS232 (Fig. 5.5). Use a RS232 serial extension cable connected to the 9-pin female serial port of the Nexus® 1250/1252 meter’s Port 1.

  • Page 78: Programming Modems For Remote Communication

    5.18: Programming Modems for Remote Communication When a modem speaks to most RS485 or RS232-based devices, it must be programmed for the communication to work. This task is often quite complicated because modems can be unpredictable when communicating with remote devices. If you are not using the EIG Modem Manager device, you must set the following strings to communicate with the remote Nexus®...

  • Page 79: Selected Modem Strings

    5.19: Selected Modem Strings Modem String/Setting Cardinal modem: AT&FE0F8&K0N0S37=9 Zoom/Faxmodem VFX V.32BIS(14.4K): AT&F0&K0S0=1&W0&Y0 Zoom/Faxmodem 56Kx Dual Mode: AT&F0&K0&C0S0=1&W0&Y0 USRobotics Sportster 33.6 Faxmodem: AT&F0&N6&W0Y0 (for 9600 baud) DIP switch setting: Up Up Down Down Up Up Up Down USRobotics Sportster 56K Faxmodem: AT&F0&W0Y0 DIP switch setting: Up Up Down Down Up Up Up Down...

  • Page 80: Irig-B Connections

    5.21: IRIG-B B Connections IRIG-B is a standard time code format that synchronizes event timestamping to within 1 millisecond. An IRIG-B signal-generating device connected to the GPS satellite system will synchronize Nexus® 1250/1252 meters located at different geographic locations. Nexus® meters use an Unmodulated signal from a satelite-controlled clock (such as Arbiter 1093B).

  • Page 81: Chapter 6: Using The Nexus® Meter's External Displays 6.1: Overview

    Chapter 6 Using the Nexus® Meter’s External Displays 6.1: Overview Electro Industries offers four external displays for use with the Nexus® 1250/1252 meter. The P40N, P41N, and P43N are LED displays that provide easy-to-use access to the information stored in your Nexus® meter. The P60N is a Touch Screen display, which provides easy access to meter readings and information with a graphical touch screen presentation.

  • Page 82: Connect Multiple Displays

    6.2.1: Connect Multiple Displays One cable (housing two-wire RS485 and two-wire power wires plus shield) is used to connect the displays. One port of the Nexus® meter supports 12 VA. Each P40N, P41N or P43N requires 3.3 VA (maximum 3.8 VA). The Master display (P40N) is the master in communication.

  • Page 83: Dynamic Readings Mode

    6.3: Dynamic Readings Mode The External Display puts itself in the Dynamic Readings Mode upon power-up. Use the Mode button to access the Dynamic Readings from other Modes. Use the Up/Down arrows to navigate from Group to Group within this Mode. See Section 6.4 for a Navigation map of the Dynamic Readings Mode.
  • Page 84 • Maximum Quadrant 1 Total PF • Minimum Quadrant 1 Total PF • Maximum Quadrant 2 Total PF • Minimum Quadrant 2 Total PF • Maximum Quadrant 3 Total PF • Minimum Quadrant 3 Total PF • Maximum Quadrant 4 Total PF •...

  • Page 85: Navigation Map Of Dynamic Readings Mode

    6.4: Navigation Map of Dynamic Readings Mode Use Left/Right arrow keys to navigate Readings Use Up/Down arrows to scroll between groups. Max %THD Min %THD Return to 1 Second Volts Maximum Volts Minimum Volts %THD Volts Volts Volts First AN,BN,CN AN,BN,CN AN,BN,CN AN,BN,CN...
  • Page 86 ® 6.5: Nexus Information Mode Use the Mode button to access the Nexus® Information mode from other modes. Use the Up/Down arrows to navigate from group to group within this mode. See Section 6.6 for a Navigation map of the Nexus® Information Mode. Group 1: Device Time •...
  • Page 87 6.6: Navigation Map of Nexus Information Mode ® Use Up/Down arrows to scroll between groups. Use Left/Right arrows to scroll between readings. Readings Meter Time Comm Return Comm Comm Comm Settings Settings Settings Settings First Reading Port 2 Port 3 Port 4 Port 1 Return...

  • Page 88: Display Features Mode

    6.7: Display Features Mode Use the Mode button to access the Display Features Mode from other modes. Use the Up/Down arrows to navigate from group to group within this mode. See Section 6.8 for a Navigation map of the Display Features mode. Group 1: Reset Max/Min Press the Enter button to reset the Max and Min values.

  • Page 89: Navigation Map Of Display Features Mode

    6.8: Navigation Map of Display Features Mode Use Up/Down arrows to scroll between groups. Reset Max/Min Reset Energy Baud Rate/Address Communication Protocol EIG Use Only EIG Use Only Lamp Test Display Scroll On/Off Electro Industries/GaugeTech Doc # E107706...

  • Page 90: Nexus® P60N Touch Screen External Display

    ® 6.9: Nexus P60N Touch Screen External Display The P60N Touch Screen external display is ready to use upon power-up. Touching the buttons at the top of the screen will take you to the groups of readings listed below. With the buttons at the bottom of the screen, you can use the touch screen to review Limits and review and/or change settings on the display and the Nexus®...
  • Page 91 VOLTS: Voltage Readings Details • Real Time Volts AN/BN/CN/AB/BC/CA • Maximum Volts AN/BN/CN/AB/BC/CA Minimum Volts AN/BN/CN/AB/BC/CA • Touch PH-N or PH-PH to view details of Phase-to-Neutral or Phase-to-Phase Readings. VOLTS: Voltage Readings PH-N • Volts AN/BN/CN Touch Back to return to the Volts main screen. VOLTS: Voltage Readings PH-PH •...
  • Page 92 AMPS: Current Readings A-B-C • Real Time Current A/B/C Touch Back to view the Amps main screen. REAL TIME POWER: Real Time Power Readings Details • Instant Watt/VAR/VA/PF • Average Watt/VAR/VA/PF Predicted Watt/VAR/VA • Touch the Demand button to go to the Demand Power screen (shown below on the right) DEMAND POWER: Demand Power Readings...
  • Page 93 TOU: Accumulations • -Watthr Quadrant 2+Quadrant 3 (Primary) • +VAhr Quadrant 2 (Primary) +VARhr Quadrant 2 (Primary) • • +VAhr Quadrant 3 (Primary) • -VARhr Quadrant 3 (Primary) • +Watthr Quadrant 1+Quadrant 4 (Primary) • +VAhr Quadrants 1 & 4 (Primary) •...
  • Page 94 FLICKER - LONG TERM • Volts A/B/C • Max Volts A/B/C Min Volts A/B/C • Touch Inst or Long Term to view other Flicker screens. NOTE: The Start button displays if Status is “Stopped”; the Stop button displays if Status is “Active.” LIMITS: Limit Status Current Limits Settings for the meters, ID 1 - 32.
  • Page 95 SPECTRUM: Harmonic Spectrum Analysis Select a Channel by touching the Channel button. Graphs and readings appear for the selected channel. Zoom In or Out for detail by touching In or Out. REAL TIME TRENDING ANALYSIS Select a Channel by touching the Channel button.
  • Page 96 LOG STATUS: Logging Statistics An Overview of the Logs for the Primary Meter. The Number of Records and Memory Used are listed for each log. RESET: Meter Reset Commands WARNING! Resets cause data to be lost. Touch the window for the Reset you want to perform. Don’t Reset changes to Reset.
  • Page 97 NEXUS® PORT SETTINGS • Port 1 (Baud and Protocol selected) • Port 2 (Baud and Protocol selected) Port 3 (Baud and Protocol selected) • • Port 4 (Baud and Protocol selected) NEXUS® METER STATUS Device Type: Nexus® 1250/1252 Meter Serial Number (10 digit number) Comm State: Healthy or Unhealthy Nv Ram: 4 MB DSP State: Healthy or Unhealthy...
  • Page 98 Electro Industries/GaugeTech 6-18 Doc #E107706...
  • Page 99 Chapter 7 Transformer Loss Compensation 7.1: Introduction The Edison Electric Institute’s Handbook for Electricity Metering, Ninth Edition defines Loss Compensation as: A means for correcting the reading of a meter when the metering point and point of service are physically separated, resulting in measurable losses including I R losses in conductors and transformers and iron-core losses.
  • Page 100 A single meter cannot measure the losses in a transformer or transmission line directly. It can, however, include computational corrections to calculate the losses and add or subtract those losses to the power flow measured at the meter location. This is the method used for loss compensation in the Nexus®...
  • Page 101 • Requires no additional wiring; the compensation occurs internally. • Imposes no additional electrical burden when performing Loss Compensation. Loss Compensation is applied to 1 second per phase Watt/VAR readings and, because of that, affects all subsequent readings based on 1 second per phase Watt/VAR readings. This method results in loss compensation being applied to the following quantities: •...

  • Page 102: Loss Compensation In Three Element Installations

    7.2.1: Loss Compensation in Three Element Installations Loss compensation is based on the loss and impedance values provided on the transformer manufacturer’s test report. A typical test report will include at least the following information: • Manufacturer • Unit Serial Number •...

  • Page 103: Three Element Loss Compensation Worksheet

    7.2.1.1: Three-Element Loss Compensation Worksheet Company Station Name Date Trf. Bank No. Trf Manf Trf Serial No. Calculation by Transformer Data (from Transformer Manufacturer’s Test Sheet) Winding Voltage Connection HV – High ∆-Y Xv – Low ∆-Y YV – Tertiary ∆-Y Value Watts Loss...
  • Page 104 Meter/Installation Data Instrument Transformers Numerator Denominator Multiplier Potential Transformers Current Transformers Power Multiplier [(Pt Multiplier) times (CT Multiplier)] Enter the Numerator and Denominator for each instrument transformer. For example, a PT with a ratio of 7200/120 has a numerator or 7200, a denominator or 120 and a multiplier of 60 (7200/120 = 60/1).
  • Page 105 = (______________) * (________________) / 100 = _______________ kVA Full-Load Loss VAR (kVAR) = SQRT((Full-Load Loss kVA)2 - (Full-Load Loss kW)2) = SQRT((_________________)2 - (________________)2) = SQRT((__________________) - (_________________)) = SQRT (_________________) = _________________ Normalize Losses to Meter Base Value at Factor Factor Quantity...
  • Page 106 Electro Industries/GaugeTech Doc #E107706...

  • Page 107: The Nexus® Meter's Tou Calendar

    Chapter 8 Time-of-Use Function 8.1: Introduction A Time-of-Use (TOU) usage structure takes into account the quantity of energy used and the time at which it was consumed. The Nexus® 1250/1252 meter’s TOU function, available with the Communicator EXT software, is designed to accommodate a variety of programmable rate structures.

  • Page 108: Tou Prior Season And Month

    8.3: TOU Prior Season and Month The Nexus® 1250/1252 meter stores accumulations for the prior season and the prior month. When the end of a billing period is reached, the current season or month becomes stored as the prior. The registers are then cleared and accumulations resume, using the next set of TOU schedules and register assignments from the stored calendar.

  • Page 109: Chapter 9: Nexus® External Output Modules

    Chapter 9 Nexus® External Output Modules 9.1: Hardware Overview All Nexus® External Output modules have the following components: • Female RS485 Side Port: use to connect to another module’s male RS485 side port. • Male RS485 Side Port: use to connect to the Nexus® 1250/1252 meter’s Port 3 or 4 or to another module’s female RS485 side port.
  • Page 110 9.1.1: Port Overview All Electro Industries Output Modules have ports through which they interface with other devices. The port configurations are variations of the three types shown below. Four Analog Outputs Eight Analog Outputs Four Relay Outputs (0-1mA and 4-20mA) (0-1mA and 4-20mA) or Four KYZ Outputs E Electro Industries/GaugeTech...
  • Page 111 9.2: Installing Nexus ® External Output Modules Output modules must use the Nexus® 1250/1252 meter’s Port 3 or 4. Six feet of RS485 cable harness is supplied. Attach one end of the cable to the port (connectors may not be supplied); insert the other end into the communication pins of the module’s Male RS485 Side Port.

  • Page 112: Power Source For Output Modules

    9.2.1: Power Source for Output Modules The Nexus® 1250/1252 meter will supply power to up to four Output Modules, depending on the type of module (Refer to module specifications, later in this chapter.) For additional modules, you must use an external power source, such as the EIG PSIO (12V). Refer to Sections 5.12 and 5.13 to determine power needed.

  • Page 113: Using Psio With Multiple Output Modules

    Communication 9.3: Using PSIO with Multiple Output Modules Only (A+, B-, and Shield) Female RS485 Side Port Control Power Mounting Mounting Bracket Reset Button Bracket I/O Port (Size and Pin Configuration Vary) Figure 9.6: Using PSIO with Multiple Output Modules NOTE: PSIO must be to the right of the Output Modules, when viewing its side label (as shown in the figure above).

  • Page 114: Factory Settings And Reset Button

    5. Once you have combined all of the Output Modules together for the group, fasten them tightly. This final tightening locks the group together as a unit. 6. Attach the right Mounting Bracket to the right side of the group using the small Phillips Head screws provided.

  • Page 115: Analog Transducer Signal Output Modules

    9.5: Analog Transducer Signal Output Modules Analog Transducer Signal Output Modules Specifications 1maAON4: 4-Channel Analog Output, 0±1mA 1mAON8: 8-Channel Analog Output, 0±1mA Model Numbers 20mAON4: 4-Channel Analog Output, 4–20mA 20mAON8: 8-Channel Analog Output, 4–20mA 0.1% of Full Scale Accuracy Programmable Scaling RS485, Modbus RTU Programmable Baud Rates: 4800, 9600, 19200, 57500...

  • Page 116: Normal Mode

    9.5.2: Normal Mode Normal Mode is the same for the 0-1mA and the 4-20mA Analog Output Modules except for the number of processes performed by the modules. Both devices: 1. Accept new values through communication. 2. Output current loops scaled from previously accepted values. The 0-1mA module includes one more process in its Normal Mode: 3.

  • Page 117: Overview

    9.6: Digital Dry Contact Relay Output (Form C) Module Digital Dry Contact Relay Output (Form C) Module Specifications 4RO1: 4 Latching Relay Outputs Model Number 0.1% of Full Scale Accuracy Programmable Scaling RS485, Modbus RTU Programmable Baud Rates: 4800, 9600, 19200, 57600 Communication 12–20V at 50–200mA;...

  • Page 118: Communication

    9.6.2: Communication Maximum registers per request, read or write, is 4 registers.orm The device operates with the following default parameters: 247 (F7H) Address 57600 Baud Baud Rate Transmit Delay Time 20csec 9.6.3: Normal Mode Normal Mode consists of one process: the device accepts new commands to control the relays.

  • Page 119: Digital Solid State Pulse Output (Kyz) Module

    9.7: Digital Solid State Pulse Output (KYZ) Module Digital Solid State Pulse Output (KYZ) Module Specifications 4PO1 Model Number RS485, Modbus RTU Communication Programmable Baud Rates: 4800, 9600, 19200, 57600 12–20V at 50–200mA; ® Nexus 1250/1252 Meter supports up to 4 Modules Power Requirement (-20 to 79)°C / (-4 to +158)°F Operating Temperature...

  • Page 120: Communication

    9.7.2: Communication Maximum registers per request, read or write, is 4 registers.orm The device operates with the following default parameters: 247 (F7H) Address 57600 Baud Baud Rate Transmit Delay Time 20csec 9.7.3: Normal Mode Energy readings are given to the device frequently. The device generates a pulse at each channel after a certain energy increase.

  • Page 121: Specifications

    9.8: Specifications Analog Transducer Signal Outputs (Up to two modules can be used with the Nexus® 1250/1252 meter.) 1mAON4: 4 Analog Outputs, scalable, bidirectional. 1mAON8: 8 Analog Outputs, scalable, bidirectional. 20mAON4: 4 Analog Outputs, scalable. 20mAON8: 8 Analog Outputs, scalable. Digital Dry Contact Relay Outputs (Multiple modules can be used.) 4RO1: 4 Relay Outputs 10 Amps, 125Vac, 30Vdc, Form C.
  • Page 122 E Electro Industries/GaugeTech 9-14 Doc #E107706...
  • Page 123 Chapter 10 Nexus® Meter with Internal Modem Option (INP2) 10.1: Hardware Overview The Nexus® 1250/1252 meter with the INP2, Internal Modem Option, has all the components of the standard Nexus® meter plus the capability of connecting to a PC via a standard phone line.

  • Page 124: Hardware Connection

    10.2: Hardware Connection Use RJ-11 Standard Telephone Line to connect with the Nexus® 1250/1252 meter. The RJ-11 line is inserted into the RJ-11 Port on the face of a Nexus® meter with the Internal Modem Option. The RJ-11 connection is virtually unlimited, since it utilizes a PSTN (Public Switched Telephone Network).
  • Page 125 Chapter 11 Nexus® Meter with Internal Network Option (INP200) Utilizing Rapid Response™ Technology 11.1: Hardware Overview The Nexus® 1250/1252 meter with the Internal Network Option (INP200) has all the components of the standard Nexus® meter, plus giving you the capability of connecting to multiple PC’s via Modbus/TCP over the Ethernet and providing a DNP LAN/WAN connection.
  • Page 126 The Internal Network Option of the Nexus® meter is an extremely versatile communications tool. The Internal Network Option: • Adheres to IEEE 802.3 Ethernet standard using TCP/IP • Utilizes simple and inexpensive 10/100BaseT wiring and connections • Plugs into your network using built-in RJ-45 jack •...
  • Page 127 Once the above parameters have been set, Communicator EXT will connect via the network using a Device Address of “1” and the assigned IP Address when you follow these steps: 1. Open Communicator EXT. 2. Click the Connect icon in the icon tool bar. The Connect screen opens. 3.
  • Page 128 Electro Industries/GaugeTech 11-4 Doc #E107706...

  • Page 129: Theory Of Operation

    Chapter 12 Flicker and EN50160 Analysis 12.1: Overview Flicker is the sensation that is experienced by the human visual system when it is subjected to changes occurring in the illumination intensity of light sources. The primary effects of Flicker are headaches, irritability and, sometimes, epileptic seizures. IEC 61000-4-15 and former IEC 868 describe the methods used to determine Flicker severity.
  • Page 130 • Block 5 performs an online statistical cumulative probability analysis of the flicker level. Block 5 allows direct calculation of the evaluation parameters Pst and Plt. Flicker Evaluation occurs in the following forms: Instantaneous, Short Term or Long Term. Each form is detailed below: •...
  • Page 131 Summary Flicker = Changes in the illumination of light sources due to cyclical voltage variations. Pinst = Instantaneous flicker values in Perceptibility Units (PU). Pst = Value based on 10-minute analysis. Plt = Value based on 12 Pst values. Measurement Procedure: 1.

  • Page 132: En50160 Flicker Polling Screen

    • Select a Pst time range from 1 to 10 minutes. The standard measurement period is nominally 10 minutes. • Select a Plt time range from 1 to 240 minutes. The standard measurement is nominally 12 Pst periods (120 minutes). Plt time must always be equal to or great than and a multiple of Pst time.
  • Page 133 • Next Plt is the countdown time to when the next Plt value is available. Status: • Indicates the current status. Active = On. Stopped = Off. Frequency: • Base is the operating frequency (50 or 60 Hz) selected in the EN50160 Flicker screen (see Section 12.3).

  • Page 134: Logging

    Long Term Readings: Click on the Long Term tab to access a screen containing three groups of Plt readings. Plt Readings Displayed: • Current Plt values for Va, Vb and Vc and the time of computation • Current Plt Max values for Va, Vb and Vc since the last reset and the time of the last reset.

  • Page 135: Doc #E107706

    12.8: Performance Notes • Pst and Plt average time are synchronized to the clock (e.g. for a 10 minute average, the times will occur at 0, 10, 20, etc.). The actual time of the first average can be less than the selected period to allow for initial clock synchronization.

  • Page 136: En50160 Configuration

    12.9: EN50160 Power Quality Compliance Analysis (Nexus® 1252 meter with V-2) If your Nexus® 1252 meter is equipped with V-Switch™ key 2, you have access to the EN50160 PQ Compliance analysis function, as well as to EN50160 Flicker measurement. 12.9.1: EN50160 Configuration 1.

  • Page 137: En50160 Analysis

    Long Term Test Time: Select the time in minutes for the LST - long-term test. The available range is 10-240 minutes, in multiples of 10 (10, 20, 30, etc.). 5. Click OK. 6. Click Update Device to send the new settings to the meter and return to the main Communicator EXT screen.
  • Page 138 Electro Industries/GaugeTech 12-10 Doc #E107706...

  • Page 139: Glossary

    Glossary 0.1 Second Values: These values are the RMS values of the indicated quantity as calculated after approximately 50 milliseconds (3 cycles) of sampling. 1 Second Values: These values are the RMS values of the indicated quantity as calculated after one second (60 cycles) of sampling.
  • Page 140 Byte: A group of 8 binary digits processed as a unit by a computer (or device) and used especially to represent an alphanumeric character. CBEMA Curve: A voltage quality curve established originally by the Computer Business Equipment Manufacturers Association. The CBEMA Curve defines voltage disturbances that could cause malfunction or damage in microprocessor devices.
  • Page 141 Flicker: Flicker is the sensation that is experienced by the human visual system when it is subjected to changes occurring in the illumination intensity of light sources. IEC 61000-4-15 and former IEC 868 describe the methods used to determine flicker severity. Harmonics: Measuring values of the fundamental current and voltage and percent of the fundamental.
  • Page 142 Modbus RTU: The most common form of Modbus protocol. Modbus RTU is an open protocol spoken by many field devices to enable devices from multiple vendors to communicate in a common language. Data is transmitted in a timed binary format, providing increased throughput and therefore, increased performance. Network: A communications connection between two or more devices to enable those devices to send and receive data to one another.
  • Page 143 Register: An entry or record that stores a small amount of data. Register Rollover: A point at which a Register reaches its maximum value and rolls over to zero. Reset: Logs are cleared or new (or default) values are sent to counters or timers. Rolling Window The Rolling (Sliding) Window Average is the average power calculated over a Average (Power):...
  • Page 144 THD: Total Harmonic Distortion is the combined effect of all harmonics measured in a voltage or current. The THD number is expressed as a percent of the fundamental. For example, a 3% THD indicates that the magnitude of all harmonic distortion measured equals 3% of the magnitude of the fundamental ®...

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