HC2S3 Temperature and Relative Humidity Probe User Manual Issued: 12.12.12 Copyright © 2005-2012 Campbell Scientific Inc. Printed under Licence by Campbell Scientific Ltd.
Guarantee This equipment is guaranteed against defects in materials and workmanship. This guarantee applies for twelve months from date of delivery. We will repair or replace products which prove to be defective during the guarantee period provided they are returned to us prepaid.
PLEASE READ FIRST About this manual Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North American market. Some spellings, weights and measures may reflect this origin. Some useful conversion factors: Area: 1 in2 (square inch) = 645 mm2 Length: 1 in. (inch) = 25.4 mm 1 ft (foot) = 304.8 mm 1 yard = 0.914 m 1 mile = 1.609 km Mass: 1 oz. (ounce) = 28.35 g 1 lb (pound weight) = 0.454 kg Pressure: 1 psi (lb/in2) = 68.95 mb Volume: 1 UK pint = 568.
Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections. 1. Introduction .................................................................. 1 2. Cautionary Statements................................................ 1 3. Initial Inspection .......................................................... 1 4. Quickstart ..................................................................... 2 5. General Description.......
Appendices A. Absolute Humidity................................................... A-1 A.1 Measurement Below 0°C ..................................................................... A-2 B. Changing the HC2S3 Temperature Range ............ B-1 B.1 B.2 B.3 B.4 HC2S3 Default Settings ....................................................................... B-1 Software and Hardware Requirements ................................................ B-1 Changing the Temperature Range ................................
HC2S3 Temperature and Relative Humidity Probe 1. Introduction The HC2S3 is a rugged, accurate temperature/RH probe that is ideal for longterm, unattended applications. The probe uses a Rotronic’s IN1 capacitive sensor to measure RH and a 100 ohm PRT to measure temperature. For optimum results, the HC2S3 should be recalibrated annually.
HC2S3 Temperature and Relative Humidity Probe 4. Quickstart 4.1 Step 1 — Mount the Probe Review Section 7.2, Installation for complete instructions. The HC2S3 is normally installed by mounting it inside a Met20 shield. 4.2 Step 2 — Use SCWin Short Cut to Program Datalogger and Generate Wiring Diagram The simplest method for programming the datalogger to measure the HC2S3 is to use Campbell Scientific's SCWin Short Cut Program Generator. 2 1. Open Short Cut and click on New Program. 2.
User Manual 3. Select HC2S3 Temperature and Relative Humidity Sensor and choose either constant power or panel switched power (uses less current), then click the right arrow to add it to the list of sensors to be measured. 4. Define the name of the public variables. Variables default to AirTC and RH that hold the air temperature and relative humidity measurements. Select the desired units of measure. Units default to Deg C.
HC2S3 Temperature and Relative Humidity Probe 4 5. Choose the outputs for the AirTC and RH and then select finish. 6. Wire according to the wiring diagram generated by SCWin Short Cut.
User Manual 5. General Description The HC2S3 is a digital probe with 0 to 1 V linear output signals for temperature and humidity, and a UART serial interface. The voltage signals can be measured with two single-ended or two differential inputs on the datalogger. A special Rotronic cable and the SDM-SIO1 Serial I/O Module or MD485 RS-485 Interface is required to interface with the UART as described in Appendix B. The D/A converter used to generate the analogue output signals has 16-bit resolution.
HC2S3 Temperature and Relative Humidity Probe 6.1 Temperature Sensor Sensor: PT100 RTD, IEC 751 1/3 Class B, with calibrated signal conditioning Temperature Measurement Range: -50°C to +100°C (default -40°C to + 60°C) Temperature Output Signal Range: 0 to 1.0 V Accuracy at 23°C: ±0.1°C with standard configuration settings Long Term Stability: <0.
User Manual RH Accuracy over Temperature: CAUTION The black outer jacket of the cable is Santoprene® rubber. This compound was chosen for its resistance to temperature extremes, moisture, and UV degradation. However, this jacket will support combustion in air. It is rated as slow burning when tested according to U.L. 94 H.B. and will pass FMVSS302. Local fire codes may preclude its use inside buildings. 6.3 Default Settings and Digital Interface Please refer to Appendices. 7. Installation 7.
HC2S3 Temperature and Relative Humidity Probe 7.2 Assembly and Mounting Attach the probe to the cable by aligning the keyed connectors, pushing the connectors together and tightening the knurled ring. When exposed to solar radiation the probe must be housed in a radiation shield such as the MET20 or MET21 naturally aspirated shield, or the 43502 motor aspiration shield (please refer to the 43502 product manual for details).
User Manual 8. Wiring Connections to Campbell Scientific dataloggers for measuring humidity and temperature using two single-ended or two differential analogue inputs are given in Tables 8-1 and 8-3. Use a single-ended analogue measurement when the cable length is less than 6.1 m (20 ft), or if power is switched off between measurements. For cable lengths longer than 6.1 m or when the probe is continuously powered, use a differential analogue measurement.
HC2S3 Temperature and Relative Humidity Probe Table 8-2.
User Manual Table 9-1. Temperature Units Multiplier (degrees mV-1) Offset (degrees) Celsius 0.1 -40 Fahrenheit 0.18 -40 Table 9-2. Humidity Units Multiplier (% mV-1) Offset (%) Percent 0.1 0 Fraction 0.001 0 9.1 Example Programs using Single-Ended Measurement Instructions The example programs for the CR1000 and CR10X use the SW12V terminal to switch power to the probe, delay for 3 seconds and measure the output voltages using single-ended measurement instructions.
User Manual Table 9-3.
User Manual CR10(X) program using single-ended measurement instructions ;{CR10X} program to measure HC2S3 with single-ended inputs *Table 1 Program 01: 5.0000 Execution Interval (seconds) 1: Do (P86) 1: 41 Set Port 1 High ;Turn on switched 12V ;Jumper from C1 to SW 12V CTRL 2: Excitation with Delay (P22) ;3-second delay 1: 1 Ex Channel 2: 0 Delay W/Ex (0.01 sec units) 3: 300 Delay After Ex (0.
HC2S3 Temperature and Relative Humidity Probe 1: 2: 3: 0 60 10 Minutes (Seconds --) into a Interval (same units as above) Set Output Flag High (Flag 0) 12: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 101 Array ID 13: Real Time (P77) 1: 1220 Year,Day,Hour/Minute (midnight = 2400) 14: Average (P71) 1: 1 Reps 2: 2 Loc [ AirTC ] 15: Sample (P70) 1: 1 2: 1 Reps Loc [ RH ] CR1000 program using single-ended measurements in Slow Sequence scan HC2S3 measurements are made every 5 seconds in a Slo
User Manual SlowSequence 'measure HC2S3 every 5 seconds Scan (5,Sec,0,0) 'HC2S3 Temperature & Relative Humidity `Note this forces and only works in sequential mode `Contact Campbell Scientific if your program must work in pipeline mode SW12(1) `switch on 12V Delay(1,3000,mSec) `delays for 3 seconds VoltSe(AirTC,1,mV2500,2,0,0,_50Hz,0.1,-40) `measure probe VoltSe(RH,1,mV2500,1,0,0,_50Hz,0.1,0) SW12(0) `switch off 12V If RH>100 AND RH<103 Then RH=100 NextScan EndProg 9.
HC2S3 Temperature and Relative Humidity Probe CR1000 program using differential measurements 'CR1000 program to measure HC2S3 with differential measurements Public AirTC Public RH DataTable(Temp_RH,True,-1) DataInterval(0,60,Min,0) Average(1,AirTC,IEEE4,0) Sample(1,RH,IEEE4) EndTable BeginProg Scan(1,Sec,1,0) 'HC2S3 Temperature & Relative Humidity Sensor measurements AirTC and RH: VoltDiff (AirTC,1,mV2500,1,True,0,_50Hz,0.1,-40) VoltDiff (RH,1,mV2500,2,True,0,_50Hz,0.
User Manual 4: If (X<=>F) (P89) 1: 4 X Loc [ RH ] 2: 4 < 3: 103 F 4: 30 Then Do 5: Z=F x 10^n (P30) 1: 100 F 2: 0 n, Exponent of 10 3: 4 Z Loc [ RH ] 6: End (P95) 7: End (P95) 8: If time is (P92) 1: 0 Minutes (Seconds --) into a 2: 60 Interval (same units as above) 3: 10 Set Output Flag High (Flag 0) 9: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 101 Array ID 10: Real Time (P77) 1: 1220 Year,Day,Hour/Minute (midnight = 2400) 11: Average (P71) 1: 1 Reps 2: 3 Loc [ AirTC ] 12: Sample (P70) 1:
HC2S3 Temperature and Relative Humidity Probe Vd = I ∗R = 2 mA ∗ 7.37 Ω 304.8 m (1000 ' ) (1) = 14.7 mV 304.8 m (1000 ' ) This voltage drop will raise the apparent temperature and relative humidity because the difference between the signal and signal reference lead, at the datalogger, has increased by Vd. The approximate error in temperature and relative humidity is 0.15°C and 0.15% per 30.5 m (100') of cable length, respectively (assuming a temperature range of -40° to +60°C).
User Manual A voltmeter can be used to check the output voltage for temperature and relative humidity on the brown and white wires respectively (temperature °C = mV * 0.1 – 40.0; relative humidity % = mV * 0.1). Symptom: Incorrect temperature or relative humidity 1. Verify the multiplier and offset parameters are correct for the desired units (Table 9-1) and temperature range. 2. Default settings are listed in Appendix A, which include the setting “Limit humidity output to 100%”.
Appendix A. Absolute Humidity The HC2S3 measures the relative humidity. Relative humidity is defined by the equation below: RH = e ∗ 100 es (A-1) where RH is the relative humidity, e is the vapour pressure in kPa , and es is the saturation vapour pressure in kPa. The vapour pressure, e, is an absolute measure of the amount of water vapour in the air and is related to the dew point temperature.
Appendix A.
Appendix B. Changing the HC2S3 Settings B.1 HC2S3 Default Settings The HC2S3 probe has the following default settings, which can be changed as described in the following sections. Additional information can be found in Rotronic’s User Manual: E-M-HC2 Probes-VXXXX, which can be downloaded from Rotronic's website www.rotronic-usa.com.
Appendix B. Changing the HC2S3 Settings IMPORTANT Prior to using the AC3001 cable, the ROTRONIC USB driver must be installed on the PC. Both the driver and the installation instructions (document E-M-HW4v3-Main) are located on the HW4 CD. B.3 Changing the Temperature Range Install the HW4 software and drivers for the AC3001 USB cable on the PC. Connect the HC2S3 probe to the AC3001 cable, making sure the connectors are properly aligned before tightening the knurled ring.
Appendix B. Changing the HC2S3 Settings Click on “Device Manager”, select “Analogue Outputs” to see the following screen: Change the lower and upper range values and click “OK”. The following screen shows the range -60 to +30: B.4 Multiplier and Offsets for Temperature Range Analogue Output 2 is 0 to 1V (1000 mV) for the temperature range.
Appendix B. Changing the HC2S3 Settings Example measurement instructions for CR1000 datalogger, with the sensor wired to SE channel 2: Public AirTC VoltSe (AirTC,1,mV2500,2,0,0,_60Hz,0.09,-60) Example measurement instruction for CR10X datalogger: 1: Volt (SE) (P1) 1: 1 2: 5 3: 2 4: 1 5: 0.09 6: -60.
Appendix C. HC2S3 Digital Communications C.1 HC2S3 Digital Interface Specifications The HC2S3 has a UART (Universal Asynchronous Receiver Transmitter) that provides two-way digital communications with the probe. Interface cables can be ordered through Rotronics for connecting the probe to an RS-485 port (Rotronic pn E2-05XX-MOD), a computer's RS-232 port (Rotronic pn AC3002), or USB port (Rotronic pn AC3001).
Appendix C. HC2S3 Digital Communications Command Format: { ID Adr RDD Chksum or } CR Adr RDD Chksum or } CR Answer format: { ID The data are returned according to the following structure: Example Type Description 1..3 Byte Probe type (1= digital probe, 2=analogue probe, 3=pressure probe) 1234.56 Float Relative humidity or analogue value %RH String Humidity or analogue value engineering unit 0..
Appendix C. HC2S3 Digital Communications C.3 RS-485 Communications using an MD485 RS-485 Interface The HC2S3 can be interfaced to a CSI datalogger through an MD485 RS-485 Interface using the Rotronic E2-05XX-MOD RS485 cable as described below. Settings for the RS485 port on the MD485 must be configured to match the configuration of the HC2S3, which are 19200 baud, No Parity, 8 Data Bits, 1 Stop bit, and No Flow Control.
Appendix C. HC2S3 Digital Communications Sensor Wiring: E2-05XX-MOD Cable MD485 Blue A Red B Green Grey/Yellow Clear NOTE CR1000 12V G Ground Symbol If the Rotronic cable includes brown and white wires (voltage signals for temperature and humidity), CSI recommends “capping” them with PN #27749 or equivalent insulated caps to prevent the possibility of shorting. Connect the CS I/O port of MD485 to CS I/O port on CR1000 with an SC12 cable.
Appendix C. HC2S3 Digital Communications RH=RH_Str TempC=TempC_Str CallTable Table1 NextScan EndProg C.4 RS-485 Communications using an SDM-SIO1 Serial I/O Module The HC2S3 can be interfaced to a CSI datalogger through an SDM-SIO1 Serial I/O Module using the Rotronic E2-05XX-MOD RS485 cable as described below.
Appendix C. HC2S3 Digital Communications Example CR1000 Program: 'CR1000 Program 'Declare variables Public SerialIndest As String * 100 Dim String_1 As String Const CRLF=CHR(13)+CHR(10) Dim HC2S3_Split(17) As String * 40 Alias HC2S3_Split(2) = RH_Str Alias HC2S3_Split(6) = TempC_Str Alias HC2S3_Split(17) = HC2S3_SN_Str Public TempC, RH, NBytesReturned Const SensorPort=32 'RH string. 'Temp string. 'HC2S3 serial number string.
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