Campbell Scientific CR10 CR10 Measurement and Control - Page 130

SECTION 9. INPUT/OUTPUT INSTRUCTIONS the excitation channel number (1X) causes the channelto be incremented with each repetition. The maximum polynomial error from -40"C to +56"C is given here: Curve Fit Error -- Range ('C) -40 to +56 -24to +48 PARAM. DATA NUMBER TYPE Error ("C) +1.0 +0.1 DESCRIPTION 01: 2 Repetitions 02.' 2 Single-ended channel number of first measurement 03: 2 Excitation channel number o4: 4 lnput location for first measurement 05: FP Multiplier 06: FP Offset Input locations altered: 1 for each thermistor channel *** 12 207 RELATIVE HUMIDITY PROBE **T FUNCTION This instruction applies a 1.5 VAC excitation across Campbell Scientific's Model 207 Temperature and RH Probe, makes a fast single-ended measurement across a series resistor, calculates the result with a Sth order polynomial, and performs the required temperature compensation before outputting the result in o/o RH. When measuring several probes, allthe RH elements should be connected sequentially. The temperature values used to correct the RH measurements should also be stored sequentially to make use of the REP feature in lnstruction 11. NOTE: The temperature value used in compensating the RH value (Parameter 5) must be obtained (see lnstruction 11) prior to executing Instruction '12 and must be in Celsius. 9-6 The RH results are placed sequentially into the input locations beginning with the first RH value In the 207 probe, the RH and temperature elements use a common excitation line. GAUTION: Never elcite the 207 probe DC excitation because the RH chip will be damaged. A 1 before the excitation channel number (1X) causes the channelto be incremented with each repetition. The maximum RH polynomial error is given here: Curve Fit Error -- Range (%RH) 10 - 100 15- 94 Error (o/"RH) +4 +1 PARAM. NUMBER 03: 05: DATA TYPE 2 2 2 4 FP FP DESCRIPTION Repetitions First single-ended channelfor RH measurement Excitation channel number Input location for first compensating temperature measurement ("C) lnput location for first R.H. measurement Multiplier Otfset Input locations altered: 1 for each RH measurement *** 13 THERMOCOUPLE TEMPERATURL, SINGLE.ENDED FUNCTION This instruction uses.the selected thermocouple calibration to calculate the thermocouple output voltage at the reference temperature, then it makes a SINGLE-ENDED VOLTAGE MEASUREMENT (Section 13.2) on the thermocouple and adds the measured voltage tothe calculated reference voltage, then converts the voltage to temperature in oC.