DUAL PROGRAMMABLE GAIN INSTRUMENTATION AMPLIFIER ONE 5-VOLT SUPPLY REQUIREDDESCRIPTIONThe EI-1040 is a dual programmable gain instrumentationamplifier with a precision reference output for bridgeexcitation. Gains are digitally selected at values of 1, 10,100, and 1000. Four TTL or CMOS- compatible addresslines individually select the amplifier gains.Applications of this device are for signal conditioning andamplification of low-level signals such as thermocouplesand transducers. This device is also used in conditioningsignals to be transmitted over a long distance to singleended receivers.The EI-1040 requires +5 volts DC at a nominal 0.1 amp.An internal DC to DC converter supplies an output of +15and –15 volts nominal. The EI-1040 consists of 2 Burr-Brown/TI PGA204 amplifiers and oneDCP010515DPB DC to DC converter.A 4.096 volt reference is provided for connection to a bridge or other device requiring excitation. Themaximum allowable current draw from this source is 5 ma.The EI-1040 can be attached to the LabJack by simply connecting the power and amplifier outputs to theLabJack. When connecting the EI-1040 to the LabJack, the LabJack should be powered down prior tomaking the connection. After the connection is made then the combination can be powered up.The gain of the EI-1040 can be programmed by the LabJack by connecting the gain select inputs GSA1,GSA2, GSB1, and GSB2 to the LabJack digital outputs. The configuration for the gain select is shownbelow:GAIN TERMINAL TERMINALGSA1 or B1 GSA2 or B21 0 010 1 0100 0 11000 1 1Combinations of gain can be selected so that for example one amplifier can have a gain of 10 and the otherhave a gain of 100. The voltage level of a 0 is typically ground and the level of a 1 is 2 volts above thedigital ground (see the PG204A spec sheet for exact levels).It should be noted that when the EI-1040/LabJack is powered from limited power sources such as notebookcomputers, bus-powered hubs, etc., there may not be enough current to supply both devices. A messagefrom the computer should tell the user of this condition.A functional block diagram of the EI-1040 is shown below.The following table describes the function of the EI-1040 terminals:LABEL DESCRIPTION LABEL DESCRIPTIONGND In POWER SOURCE GROUND GND SIGNAL GROUND+5 In 5 VOLT FROM POWER SOURCE -15V OUT -15 VOLT USER AT 8 ma *+5 In SPARE 5 VOLT TERMINAL +15V OUT +15 VOLT USER AT 8 ma *GSB2 GAIN STATE B2 EXCT 4.096 VOLT FOR EXCITATION **GSB1 GAIN STATE B1 B- In B AMP MINUS INPUTGSA2 GAIN STATE A2 B+ In B AMP PLUS INPUTGSA1 GAIN STATE A1 GND SIGNAL GROUNDB Out B AMPLIFIER OUTPUT A- In A AMP MINUS INPUTA Out A AMPLIFIER OUTPUT A+ In A AMP PLUS INPUT* Worst case current availability - actual current availability may be greater** Current availability is 3 ma maxThe instrumentation amplifiers used are Texas Instruments/ Burr Brown PGA204 parts. The specificationsfor these parts can be obtained on Internet at:http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=PGA204Typical applications for this unit include: SIGNAL CONDITIONER, THERMOCOUPLE AMPLIFIER,STRAIN GAUGE AMPLIFIER, DATA ACQUISITION APPLICATIONS, SIGNAL FILTER, AUDIOAMPLIFIER, MICROPHONE AMPLIFIERFOR TECHNICAL SUPPORT CONTACT:ELECTRONIC INNOVATIONS CORP3333 S. WADSWORTH BLVD. UNIT A104LAKEWOOD CO 80227303-987-2441 FAX 303-980-6581 - Email: [email protected] Web: