3WHB10K 3-Wire Half Bridge Terminal Input Module Revision: 12/06 H L G H L AG H L AG C o p y r i g h t © 1 9 9 6 - 2 0 0 6 C a m p b e l l S c i e n t i f i c , I n c .
Warranty and Assistance The 3WHB10K 3-WIRE HALF BRIDGE TERMINAL INPUT MODULE is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
WHB10K Table of Contents PDF viewers note: These page numbers refer to the printed version of this document. Use the Adobe Acrobat® bookmarks tab for links to specific sections. 1. Function........................................................................1 2. Specifications ..............................................................1 3. Wiring............................................................................2 4. Programming Examples..............................................2 4.1 4.
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3WHB10K 3-Wire Half Bridge Terminal Input Module 1. Function Terminal input modules connect directly to the datalogger's input terminals to provide completion resistors for resistive bridge measurements, voltage dividers, and precision current shunts. H L G H L AG H L AG FIGURE 1-1. Terminal Input Module 2. Specifications 10 kOhm Completion Resistor Tolerance @ 25°C Temperature coefficient 0°-60°C -55°-125°C Power rating @ 70°C ±0.01% ±4 ppm/°C ±8 ppm/°C 0.
3WHB10K 3-Wire Half Bridge Terminal Input Module 3. Wiring Datalogger Vx 10 kΩ H H L L or AG G or G A B Shield FIGURE 3-1. 3-Wire Half Bridge Used to Measure PRT TABLE 3-1. 3WHB10K Connections to Campbell Scientific Dataloggers Function Label/Lead CR10X, CR510 Excitation V1 Reference V2 Sense Ground Black Wire H L G E1 SE1 SE2 AG CR23X, CR1000, CR800, CR850, CR3000 EX1 SE1 SE2 21X, CR7, CR9000X Excitation 1 1H 1L 4.
3WHB10K 3-Wire Half Bridge Terminal Input Module TABLE 4-1. Excitation Voltage for 100 Ohm PRT in 3WHB10K Based on Maximum Temperature and Input Voltage Range Max. Temp °C 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 PRT Resistance Ohms 119.4 138.5 157.31 175.84 194.07 212.02 229.67 247.04 264.11 280.9 297.39 313.59 329.51 345.13 360.47 375.51 390.
3WHB10K 3-Wire Half Bridge Terminal Input Module 4.2 21X 1: 3W Half Bridge (P7) 1: 1 Reps 2: 3 ± 50 mV Slow Range 3: 1 SE Channel 4: 1 Excite all reps w/Exchan 1 5: 4200 mV Excitation 6: 1 Loc [ Rs_R0 ] 7: 100 Mult 8: 0 Offset 2: Temperature RTD (P16) 1: 1 Reps 2: 1 R/RO Loc [ Rs_R0 3: 2 Loc [ Temp_C ] 4: 1.0 Mult 5: 0 Offset ] 4.
3WHB10K 3-Wire Half Bridge Terminal Input Module 4.4 CR9000X 'CR9000X Datalogger Public RS_Ro, Temp_F DataTable (Temp_F,1,-1) DataInterval (0,0,0.10) Sample (1,Temp_F,FP2) EndTable BeginProg Scan (1,mSec,0,0) BrHalf3W (Rs_Ro,1,V50,5,1,6,1,1,4200,True,30,40,100,0) PRT (Temp_F,1,Rs_Ro,1.8,32) CallTable Temp_F NextScan EndProg 4.
3WHB10K 3-Wire Half Bridge Terminal Input Module The result of the 3-wire half bridge instruction is equivalent to the ratio of the PRT resistance, Rs to the resistance of the 10 k fixed resistor, Rf. Rs Rf The RTD Instruction (16) computes the temperature (°C) for a DIN 43760 standard PRT from the ratio of the PRT resistance at the temperature being measured (Rs) to its resistance at 0°C (R0).
3WHB10K 3-Wire Half Bridge Terminal Input Module To perform the calibration, connect the PRT to the datalogger and program the datalogger to measure the PRT with the 3-wire half bridge as shown in the example section. For a 100 Ohm PRT use a multiplier of 100; for a 1000 Ohm PRT use a multiplier of 10. Place the PRT in an ice bath (@ 0°C; Rs=R0). Read the result of the bridge measurement. The reading is Rs/Rf, which is equal to R0/Rf since Rs=R0.
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