CCS WattNode Pulse Output Manuals

WATTNODE ® Pulse Output Installation and Operation Manual Continental Control Systems http://www.ccontrolsys.com Rev 1.20eUL Information in this document is subject to change without notice. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without the prior written permission of Continental Control Systems, LLC. ©2007 Continental Control Systems, LLC. All rights reserved. Printed in the United States of America. Document Number: WNP-UL-1.20 Revision Date: March 5, 2007 Continental Control Systems, LLC. 3131 Indian Rd., Suite A Boulder, CO 80301 (303) 444-7422 FAX: (303) 444-2903 E-mail: [email protected] Web: http://www.ccontrolsys.com WattNode is a registered trademark of Continental Control Systems, LLC. FCC INFORMATION This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area can cause harmful interference in which case the user will be required to correct the interference at his own expense. Contents 1 Contents OVERVIEW................................................................................................................. 2 WattNode....................................................................................................................................................2 Current Transformers..................................................................................................................................2 Optoisolator Output ....................................................................................................................................2 INSTALLATION.......................................................................................................... 2 Precautions..................................................................................................................................................3 Measurement Configurations......................................................................................................................3 Single-Phase Two-Wire .......................................................................................................................4 Single-Phase Three-Wire .....................................................................................................................5 Three-Phase Four-Wire Wye................................................................................................................6 Three-Phase Three-Wire Delta.............................................................................................................7 Mounting.....................................................................................................................................................8 Current Transformers..................................................................................................................................9 Approved Current Transformers ..........................................................................................................9 Connecting Current Transformers........................................................................................................9 Connecting Voltage Terminals .................................................................................................................10 Connecting Output....................................................................................................................................11 Installation Summary................................................................................................................................12 Installation Troubleshooting.....................................................................................................................13 OPERATING INSTRUCTIONS................................................................................. 15 Power and Energy Computation ...............................................................................................................15 Scale Factors.............................................................................................................................................16 Specifications............................................................................................................................................16 Models................................................................................................................................................16 Current Transformers .........................................................................................................................16 Accuracy.............................................................................................................................................17 Electrical.............................................................................................................................................17 Environmental ....................................................................................................................................17 Mechanical .........................................................................................................................................17 WARRANTY............................................................................................................. 18 2 Overview Overview WattNode Congratulations on your purchase of the WattNode ®, the most compact instrumentation-grade watt/watt- hour transducer available. Using state-of-the-art ASIC and surface mount components, the WattNode offers precision energy and power measurements in a compact package. The WattNode enables you to make precise power and energy measurements from within existing electric service panels avoiding the costly installation of subpanels and associated wiring. The WattNode is designed for use in demand side management (DSM), sub-metering, and energy monitoring applications where accuracy at reasonable cost is essential. The WattNode outputs a stream of pulses whose frequency is proportional to the instantaneous power and whose count is proportional to total watt-hours. Models are available for single-phase, three- phase wye and three-phase delta configurations for voltages from 120 VAC to 600 VAC at 50 to 60 Hz. Current Transformers The WattNode uses either toroidal or split-core (opening) current transformers (CTs). The WattNode requires CTs with burden resistors generating 0 – 0.333 VAC. Split-core CTs offer greater ease of installation, because they can be installed without disconnecting the circuit being measured (although connecting the voltage terminals on the WattNode requires that at least one circuit in the service panel be turned off). Toroidal CTs are more compact, more accurate and less expensive, but installation requires that the measured circuit be disconnected. The rated current of the CTs should normally be chosen at or above the maximum current of the circuit being measured. However, if the circuit will normally operate at some fraction of the maximum current and greatest accuracy is desired at the normal operating power levels, then a CT rated somewhat above the normal operating current may be a better choice. Take care that the maximum allowable current for the CT can not be exceeded without tripping a circuit breaker or fuse (see Table 4: Scale Factors) WattNode can measure up to 150% of rated maximum power for the chosen voltage range and CT, but accuracy will suffer as the CT’s core begins to saturate. CTs are also nonlinear at very low power levels and may report less than the true current. CTs can measure lower currents than they were designed for by passing the wire through the CT more than once. For example, to measure currents up to 1 amp with a 5 amp CT, pass the wire through the CT once, then loop back around the outside of the CT, and pass the wire through the CT again. Repeat until the wire passes through the CT 5 times. The CT is now effectively a 1 amp CT instead of a 5 amp CT. In general, the current rating of the CT is divided by the number of times that the wire passes through the CT. Optoisolator Output The pulse output of the WattNode passes through an optoisolator to provide 2500 volts of isolation. This allows the WattNode to be interfaced to monitoring or data logging hardware without concern about interference, ground loops, shock hazard, etc. The standard output frequency WattNodes (2.667Hz and 4.000Hz) produce a square-wave output with a duty cycle very close to 50%. The higher output frequency models generate a less regular output waveform, since variations in the measured power during a single cycle appear in the output. The medium output frequency WattNodes (193.3Hz and 290.0 Hz) produce a varying square-wave with random fluctuations from 25% to 75% duty cycle. The highest output frequency WattNodes (773.3Hz and 1160Hz) produces a waveform with narrow pulses and varying pulse spacing.Installation