Omega DMD-476 User's Manual
Contents
1. Terminal Strip Assignments Screw Screw _ Function a SENSE SWA4 SWAS Spar Range 40 mV to 50 mV 20 mV to 40 mV 10 mV to 20 mV 5 mV to 10 mV EXCITATION KE SENSE SIGNAL EXCITATION OUTPUT AC RETURN Getting Started with the Model DMD 476 1 Excitation Supply If remote sensing is not used connect Sense to Excitation terminal 3 to 4 and connect Sense to Excitation terminal 1 to 2 Apply power to the DMD 476 and adjust the Excitation supply Turn SWB 1 ON for a fixed 10 Volts This will set the supply to 10 2 2 5 and provide the best temperature stability For voltages between 5 and 10 Volts place SWB 1 in the OFF position and set the Excitation Supply with potentiometer E SWB 2 may be in either position Turn the power to the DMD 476 off and connect the load cell to the DMD 476 Excitation terminals and the Amplifier Inputs 4 Turn on power to the DMD 476 5 Turn SWA 3 ON To set output ZERO current with pot D 6 Select the expected full scale signal range according to the table with SWA 4 and SWA 5 If the output from the load cell is not known set both SW 4 and SW 5 ON for the 40 50mV range 7 Set SWA 2 OFF for 4mA or SWA 2 ON for OmA output ZERO 8 Adjust D potentiometer for desired ZERO current 9 Turn SWA 3 OFF Expect output current to change2. Users Guide SE O An OMEGA Technologies Company http www omega com e mail info omega com DMD 476 Bridgesensor AC Powered Signal Conditioner omega com LE OMEGN OMEG Anet On Line Service Internet e mail http www omega com info omega com USA ISO 9001 Certified Canada Servicing North America One Omega Drive Box 4047 Stamford CT 06907 0047 Tel 203 359 1660 FAX 203 359 7700 e mail info omega com 976 Bergar Laval Quebec H7L 5A1 Tel 514 856 6928 FAX 514 856 6886 e mail info omega ca For immediate technical or application assistance USA and Canada Mexico and Latin America Benelux Czech Republic France Germany Austria United Kingdom ISO 9002 Certified Sales Service 1 800 826 6342 1 800 TC OMEGASM Customer Service 1 800 622 2378 1 800 622 BESTSM Engineering Service 1 800 872 9436 1 800 USA WHENSM TELEX 996404 EASYLINK 62968934 CABLE OMEGA Tel 95 800 826 6342 FAX 95 203 359 7807 En Espafiol 95 203 359 7803 e mail espanol omega com Servicing Europe Postbus 8034 1180 LA Amstelveen The Netherlands Tel 31 20 6418405 FAX 31 20 6434643 Toll Free in Benelux 0800 0993344 e mail nl omega com ul Rude armady 1868 733 01 Karvina Hranice Tel 420 69 6311899 FAX 420 69 6311114 Toll Free 0800 1 66342 e mail czech omega com 9 rue Denis Papin 78190 Trappes Tel 33 130 621 400 FAX 33 130
3. 10 11 12 13 14 15 Apply no load or dead weight to load cell Adjust TARE potentiometers A and B for the same ZERO current set in Step 8 SWA 1 OFF provides a bridge output balance of 3mV to 15mV and ON between 15mV and 25mV Apply full scale load and adjust SPAN GAIN potentiometer C for the desired full scale output current Set Range switches SWA 4 and SWA 5 as required Remove full scale load and check ZERO output current Adjust FINE TARE potentiometer A ifrequired Recheck full scale as in Step 12 End Note If the amplifier is used without using the DMD 476 Excitation Supply the external power supply low side must be connected to the EXCITATION terminal 2 on the Model DMD 476 or one of the inputs must be tied to terminal 2 EXCITATION This provides a DC return path for the finite amplifier input current Amplifier The amplifier is a true differential input low drift Instrumentation Amplifier with less than 100pA input current It has a common mode range of 5 Volts with respect to the EXCITATION supply terminal and a minimum of 100dB rejection of the common mode voltage The input amplifier and excitation supply are DC isolated from the AC line and the current output The isolated output current source has a compliance of 20 Volts to allow the Model DMD 476 to operate with zero to 1000 Ohms of loop resistance Tare Weight Compensation The Model DMD 476 has two different zero controls
4. under warranty and Model and serial number of product and Repair instructions and or specific problems Repair instructions and or specific problems relative to the product relative to the product OMEGA s policy is to make running changes not model changes whenever an improvement is possible This affords our customers the latest in technology and engineering OMEGA is a registered trademark of OMEGA ENGINEERING INC Copyright 1999 OMEGA ENGINEERING INC All rights reserved This document may not be copied photocopied reproduced translated or reduced to any electronic medium or machine readable form in whole or in part without the prior written consent of OMEGA ENGINEERING INC Where Do I Find Everything I Need for M 3241 8 Process Measurement and Control OMEGA Of Course TEMPERATURE M Thermocouple RTD amp Thermistor Probes Connectors Panels amp Assemblies M Wire Thermocouple RTD amp Thermistor M Calibrators amp Ice Point References M Recorders Controllers amp Process Monitors M Infrared Pyrometers PRESSURE STRAIN AND FORCE M Transducer amp Strain Gauges M Load Cells amp Pressure Gauges M Displacement Transducers M Instrumentation amp Accessories FLOW LEVEL M Rotameters Gas Mass Flowmeters amp Flow Computers M Air Velocity Indicators M Turbine Paddlewheel Systems M Totalizers amp Batch Controllers pH CONDUCTIVITY M pH Electrodes Testers amp Accessori
5. 20 mA Output Output Capable of Driving 1000 ohm Loop Bridge Balance with 80 Tare Offset Capability m High Gain Amplifier Can Accept Full Scale Live Load Signals as Low as 5 mV and Provide 16 mA Output Span Excitation Supply Capable of Driving Four Load Cells AC Powered Rugged Epoxy Encapsulated Design Applications Weighing with Load Cells Process Control Add on Loops Can Be Used With All Types of Low Output Sensors Specifications NOTE Unless otherwise noted specifications apply after one hour warm up at 25 C ambient Temperature coefficients apply between 0 and 55 C ambient 700 VDC 60pF Input to Output Adjustment Range Input for 4 20 mA Output Linearity Temperature Stability 5 mV to 50 mV 0 01 of Full Scale 50 PPM 0 005 C 1 Hz to 10 Hz Tare Adjustment Range 2 VP P 3 mV to 25 mV Equals 80 F S of 3 mV V cell Bridge Offset nput Resistance Differential and Common Mode 1000 megohm Common Mode Rejection DC 100 dB minimum Common Mode Input 5 Volts Zero Adjust 0 or 4 mA Temperature Coefficient 1uA C 1 to 20 Volts 1 mA to 20 mA to 1000 ohms 0 Hertz 2 Pole Roll Off Response Time Rise Time 10 to 90 To 0 1 of Final Value 100 ms 5 to 10 Volts Temperature Coefficient 100 PPM Typical Fixed 10 2V 2 5 Temperature Coefficient 60 PPM Typical oad Current to 120 mA Regulation Load and Line 02 maximum Output Noise 120 Hz Band
6. 699 120 Toll Free in France 0800 4 06342 e mail france omega com Daimlerstrasse 26 D 75392 Deckenpfronn Germany Tel 49 07056 3017 FAX 49 07056 8540 Toll Free in Germany 0130 11 21 66 e mail info omega de One Omega Drive River Bend Technology Centre Northbank Irlam Manchester M44 5EX England Tel 44 161 777 6611 FAX 44 161 777 6622 Toll Free in the United Kingdom 0800 488 488 e mail info omega co uk It is the policy of OMEGA to comply with all worldwide safety and EMC EMI regulations that apply OMEGA is constantly pursuing certification of its products to the European New Approach Directives OMEGA will add the CE mark to every appropriate device upon certification The information contained in this document is believed to be correct but OMEGA Engineering Inc accepts no liability for any errors it contains and reserves the right to alter specifications without notice WARNING These products are not designed for use in and should not be used for patient connected applications Description The Model DMD 476 is a self contained AC powered signal conditioner for bridge type instrumentation It contains a precision instrumentation amplifier with isolated filtered output and ahighly regulated low noise adjustable Output bridge excitation source The unit is completely encapsulated for use in rugged environments Features Complete Strain Gage Bridge Signal Conditioner Isolated 4 20 mA or 0
7. One is called the OUTPUT zero and can be set to OmA or 4mA with SWA 2 The other zero control is called TARE SWA 1 allows the selection of one of two TARE ranges 3mV to 15mV or 15mV to 25mV Potentiometers are available for COARSE and FINE TARE adjustments Connecting to a Sensor Any amplifier has a finite input current which must have DC return path to the amplifier power supplies This path is automatically provided when the Model DMD 476 Bridge Excitation Supply is used to excite the sensor If an external supply is used one side of the external supply must be connected to the DMD 476 common Terminal 2 Be sure that the common mode voltage limits are observed This would generally limit the external power supply to 10 Volts assuming that half the voltage would be common mode as is the case when exciting a full bridge When the full scale output of a sensor is measured in millivolts say 10 millivolts care must be exercised in wiring systems At 10 millivolts full scale each microvolt 10 8 volts contributes 0 01 of full scale output Wire connections can generate microvolts of potential due to contact potentials These will also be thermoelectric potentials and thus vary with temperature differences All wires used in connecting up the Model DMD 476 should be of the same material If any intervening connections are made such as a terminal block the terminal block connecting points should have good thermal contact so they will always be
8. at the same temperature and thus cancel each other Transducer Excitation The bridge excitation supply voltage is set by SWB 1 and potentiometer E Set SWB 1 ON for a fixed 10 Volts This will provide the best temperature stability The supply can be adjusted between 5 and 10 Volts by setting SWB 1 OFF and adjusting potentiometer E The supply will deliver up to 120mA current at any voltage setting to power up to four 350 ohm sensors Hees VW RRANTY DISCLAIMER me OMEGA ENGINEERING INC warrants this unit to be free of defects in materials and workmanship for a period of 13 months from date of purchase OMEGA Warranty adds an additional one 1 month grace period to the normal one 1 year product warranty to cover handling and shipping time This ensures that OMEGA s customers receive maximum coverage on each product If the unit malfunctions it must be returned to the factory for evaluation OMEGA s Customer Service Department will issue an Authorized Return AR number immediately upon phone or written request Upon examination by OMEGA if the unit is found to be defective it will be repaired or replaced at no charge OMEGA s WARRANTY does not apply to defects resulting from any action of the purchaser including but not limited to mishandling improper interfacing operation outside of design limits improper repair or unauthorized modification This WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evid
9. ence of having been damaged as a result of excessive corrosion or current heat moisture or vibration improper specification misapplication misuse or other operating conditions outside of OMEGA s control Components which wear are not warranted including but not limited to contact points fuses and triacs OMEGA is pleased to offer suggestions on the use of its various products However OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any damages that result from the use of its products in accordance with information provided by OMEGA either verbal or written OMEGA warrants only that the parts manufactured by it will be as specified and free of defects OMEGA MAKES NO OTHER WARRANTIES OR REPRESENTATIONS OF ANY KIND WHATSOEVER EXPRESS OR IMPLIED EXCEPT THAT OF TITLE AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED LIMITATION OF LIABILITY The remedies of purchaser set forth herein are exclusive and the total liability of OMEGA with respect to this order whether based on contract warranty negligence indemnification strict liability or otherwise shall not exceed the purchase price of the component upon which liability is based In no event shall OMEGA be liable for consequential incidental or special damages CONDITIONS Equipment sold by OMEGA is not intended to be used nor shall it be used 1 as a Basic Compo
10. es M Benchtop Laboratory Meters M Controllers Calibrators Simulators amp Pumps M Industrial pH amp Conductivity Equipment DATA ACQUISITION M Data Acquisition amp Engineering Software M Communications Based Acquisition Systems M Plug in Cards for Apple IBM amp Compatibles M Datalogging Systems M Recorders Printers amp Plotters HEATERS M Heating Cable M Cartridge amp Strip Heaters M Immersion amp Band Heaters M Flexible Heaters M Laboratory Heaters ENVIRONMENTAL MONITORING AND CONTROL M Metering amp Control Instrumentation M Refractometers M Pumps amp Tubing M Air Soil amp Water Monitors M Industrial Water amp Wastewater Treatment M pH Conductivity amp Dissolved Oxygen Instruments
11. nent under 10 CFR 21 NRC used in or with any nuclear installation or activity or 2 in medical applications or used on humans Should any Product s be used in or with any nuclear installation or activity medical application used on humans or misused in any way OMEGA assumes no responsibility as set forth in our basic WARRANTY DISCLAIMER language and additionally purchaser will indemnify OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the Product s in such a manner m RETURN REQUESTS INQUIRIES me Direct all warranty and repair requests inquiries to the OMEGA Customer Service Department BEFORE RETURNING ANY PRODUCT S TO OMEGA PURCHASER MUST OBTAIN AN AUTHORIZED RETURN AR NUMBER FROM OMEGA S CUSTOMER SERVICE DEPARTMENT IN ORDER TO AVOID PROCESSING DELAYS The assigned AR number should then be marked on the outside of the return package and on any correspondence The purchaser is responsible for shipping charges freight insurance and proper packaging to prevent breakage in transit FOR WARRANTY RETURNS please have the FOR NON WARRANTY REPAIRS consult OMEGA following information available BEFORE contacting for current repair charges Have the following OMEGA information available BEFORE contacting Purchase Order number under which the OMEGA product was PURCHASED Purchase Order number to cover the COST Model and serial number of the product of the repair
12. width mV RMS maximum 115 VAC 10V 50 60 Hz Power Input 100 220 or 230 VAC 10 Line Isolation Capacitance 60 pF Dielectric Withstand 1100 Volts RMS Ambient Operating 25 C to 55 C 18 oz 510 grams 3 75 L x 2 0 W x 2 87 H 9 53 cm x 5 1 cm x 7 62 cm MODEL DMD 476 Block Diagram TARE SPAN GAIN ZERO CURRENT ADJUST ADJUST ADJUST IN z INSTRUMENTATION 2 CURRENT AMPLIFIER OUTPUT IN 3 EXCITATION COMMON LOOP RETURN Il 4 SENSE SENSE BRIDGE EXCITATION SUPPLY 5V 10V EXCITATION 120mA MAX td SWB AC POWER INPUT EXCITATION SWB Excitation Voltage Mechanical Specifications ON FOR FIXED 10V NOT USED or pe ONE EXCITATION EXCITATION ADJUST gr 2 1 00 do LI 0 25 THRU 2 00 COARSE TARE SWB 1 Excitation Voltage FINE TARE ON Fixed 10 Volts i OFF Adjustable DER La 3 25 OUTPUT ZERO lt 378 SWA Control Switch ZERO CURRENT SELECT ZERO CURRENT ON TO ADJUST POT D TARE RANGE SELECT SPAN RANGE SELECTION 12345 Roo io fol oa SWAT OFF 3mV to 15 mV ON 15 mV to 25 mV SWA2 ru OFF 4 mA ON 0 mA TOP VIEW
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