Campbell Scientific CR1000KD CR800 and CR850 Measurement and Control Systems - Page 297
Thermocouple, 1.5 Pulse - cr1000 datalogger
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Section 8. Operation Table 63. StrainCalc() Instruction Equations StrainCalc() BrConfig Code Configuration Full-bridge strain gage. Half the bridge has two gages parallel to + and - , and the other half to - and + : 6 where: • : Poisson's Ratio (0 if not applicable) • GF: Gage Factor • Vr: 0.001 (Source-Zero) if BRConfig code is positive (+) • Vr: -0.001 (Source-Zero) if BRConfig code is negative (-) and where: • "source": the result of the full-Wheatstone-bridge measurement (X = 1000 * V1 / Vx) when multiplier = 1 and offset = 0. • "zero": gage offset to establish an arbitrary zero (see FieldCalStrain() in FieldCal() Demonstration Programs (p. 154) ). StrainCalc Example: See FieldCalStrain() Demonstration Program (p. 162) 8.1.4 Thermocouple Thermocouples are easy to use with the CR800. They are also inexpensive. However, even though the Quickstart Tutorial (p. 33) uses a thermocouple as an exercise in measurement, the CR800 is not designed for accurate thermocouple measurements when thermocouples are attached directly to the CR800 wiring panel. The lack of an insulating wiring terminal cover and the nature of the plastic encasement will probably induce significant error in the reference junction temperature measurement. If an external reference junction is to be used, Campbell Scientific strongly encourages users to carefully evaluate relevant parts of the Thermocouple Measurements section of the CR1000 Datalogger Operator's Manual, which is available at www.campbellsci.com. 8.1.5 Pulse Figure Pulse-Sensor Output Signal Types (p. 39) illustrates pulse input types measured by the CR800. Figure Switch-Closure Pulse Sensor (p. 298) is a generalized schematic showing connection of a pulse sensor to the CR800. The CR800 features two dedicated pulse-input channels, P1 through P2, and four digital I/O channels, C1 through C4, for measuring frequency or pulse output sensors. As shown in table Pulse-Input Channels and Measurements (p. 39), all CR800 pulse-input channels can be measured with CRBasic instruction PulseCount(). PulseCount() has various parameters to customize it to specific applications. Digital I/O ports C1 through C4 can also be measured with the TimerIO() 297