B&B Electronics I-7011 user manual

Page 64

To measure the Seebeck voltage directly is not available because we must first connect a voltmeter to the thermocouple, and the voltmeter leads themselves create a new thermoelectric circuit. Therefore we need to eliminate the junction thermoelectric to measure the correct Seebeck voltage, and this is called “Cold Junction Compensation”.

For most thermocouples, the Seebeck voltage is 0V while in 0°C. One simple way to cancel the junction voltage is to put the junction into 0°C enviroment and the junction voltage is 0V. Nor- mally, this is not a good method for most application. Typical method is to measure the junction temperature by thermistor, and measure the junction voltage from the junction temperature. Then we may get the Seebeck voltage from measured thermocouple voltage and junction voltage, and we may calculate the temperature from the Seebeck voltage.

I-7011, I-7018 User Manual

Rev:B1.0

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Contents Copyright WarrantyTrademark Table of Contents @AADOData High/Low Alarm Introduction More InformationPin Assignment RevB1.0 Specifications 7011/I-7011D7011P/I-7011PD 7018 7018PBlock Diagram Wire Connection Page Jumper Setting Default SettingQuick Start Calibration Don’t Perform Calibrate Until You Really UnderstandBaudrate Setting CC Analog Input Type Setting TT Configuration TablesData Format Setting FF Analog input type and data format table Type Input Range Data Format +F.S Zero CodeRevB1.0 Type Input Range Data Format +F.S Zero Code Command Sec.2.19 Related Command Syntax %AANNTTCCFFCHKcrAACHKcr ?AACHKcrSyntax #**CHKcr Example#AA Syntax #AACHKcr#AAN Response Valid Command DataCHKcr Invalid Command ?AACHKcrSyntax #AANCHKcr $AA0 Syntax $AA0CHKcr$AA1 Syntax $AA1CHKcr$AA2 Syntax $AA2CHKcrAATTCCFFCHKcr FF data format of module reference Sec.1.10 Example$AA3 Syntax $AA3CHKcr$AA4 Syntax $AA4CHKcrAASDataCHKcr Data synchronized data, format reference Sec.1.10 Example10 $AA5VV Syntax $AA5VVCHKcrSyntax $AA6CHKcr 11 $AA6AAVVCHKcr Syntax $AA8CHKcr 12 $AA8AAVCHKcr 13 $AA8V Syntax $AA8VCHKcrRelated Command Sec.2.8 $AA3 14 $AA9DataSyntax $AA9DataCHKcr AA address of response module 00 to FF ExampleSyntax $AABCHKcr 15 $AABAASCHKcr Syntax $AAFCHKcr 16 $AAFAADataCHKcr 17 $AAM Syntax $AAMCHKcr18 $AAZData Syntax $AAZDataCHKcr19 ~AAOData Read address 01 module name, return 7018. Related CommandSyntax ~AAODataCHKcr Syntax ~AAEVCHKcr 20 ~AAEVRelated Topic 21 @AADI Syntax @AADICHKcrAASOOIICHKcr Level. ExampleHigh 22 @AADOData 23 @AAEAT Syntax @AAEATCHKcr24 @AAHIData 25 @AALOData 26 @AADA Related Command Sec.2.23 @AAEAT Related TopicSyntax @AADACHKcr 27 @AACA Syntax @AACACHKcr28 @AARH Read address 01 high alarm, return +2.5000. Related CommandSyntax @AARHCHKcr 29 @AARL 30 @AARE Read address 01 event counter, return 1234. Related CommandSyntax @AARECHKcr 31 @AACE Syntax @AACECHKcr32 ~ Description Host OKSyntax ~**CHKcr Response No response. ExampleHost watchdog timeout flag, 0=Clear, 1=Set Example 33 ~AA0Syntax ~AA0CHKcr AASSCHKcr34 ~AA1 Syntax ~AA1CHKcr35 ~AA2 Syntax ~AA2CHKcr36 ~AA3EVV Syntax ~AA3EVVCHKcr37 ~AA4 Syntax ~AA4CHKcrAAPPSSCHKcr SS Safe Value, data format is same as PP Example38 ~AA5PPSS Syntax ~AA5PPSSCHKcrINIT* pin Operation Module StatusDual Watchdog Operation Digital Input and Event CounterDigital Output Dual Watchdog = Module Watchdog + Host WatchdogHigh/Low Alarm Thermocouple Measurement