Measurements of Sap Flow by the Heat-Pulse Method.
Summary Heat-pulse techniques can be used to measure sap flow in plant stems with minimal disruption to the sap stream (Swanson and Whitfield, 1981; Cohen et al., 1981; Green and Clothier, 1988). The measurements are reliable, use inexpensive technology, provide a good time resolution of sap flow, and they are well-suited to automatic data collection and storage. Sequential or simultaneous measurements on numerous trees are possible, permitting the estimation of transpiration from whole stands of trees.
Contents Summary 1. .. .. .. .. .. .. .. .. .. 2 Background and Theory .. .. .. .. .. .. 5 1.1 The origin of heat-pulse .. .. .. .. .. 5 1.2 Idealized heat-pulse theory .. .. .. .. .. 5 1.3 Wound corrections to the heat-pulse theory .. .. .. 6 1.4 Converting heat-pulse velocity to sap flow .. .. .. 10 1.5 Measuring the volume fractions, FM and FL .. .. .. 10 1.6 Estimating volumetric sapflow .. 11 .. .. .. .. 12 3.
6. 7. 5.8 Operation of the logger program - C21-HP4.DLD .. .. 24 5.9 Listing of the logger program - .. .. 25 C10-HP4.CSI Running the analysis software .. .. .. .. .. 28 6.1 Files in A:\FORT .. .. .. .. .. .. 28 6.2 Setting up the input file .. .. .. .. .. 28 6.3 Examining the output file .. .. .. .. .. 30 6.4 Listing of the ANALYSIS program .. .. .. .. 31 44 References .. .. .. .. .. .. .. .. Appendix A: Use of an AM25T multiplexer .. .. .. ..
1. 1.1 Background and Theory The Origin of Heat-pulse Heat-pulse methods date back some 60 years to the work of Huber (1932) who first conceived the idea of using heat as a tracer of sap flow. In his early experiments on tropical liana, Huber found such high rates of sap flow that when heat was applied for one to two seconds it was still recognizable as a pulse at the junctions of a thermocouple sensor some 30 cm downstream from the heater.
be inserted radially into the plant stem, with the temperature being measured at a point far enough below the surface of the stem to avoid the unknown losses of heat which had previously reduced the usefulness of Huber’s method. Marshall’s (1958) work was based on an analytical solution to the idealized heat flow equation. He used this theory to calculate the temperature rise at any point in the sapwood following the application of an instantaneous line source of heat.
Figure 1. Arrangement of sensors within a plant stem for the compensation heatpulse method.
probes, and by the disruption of xylem tissue associated with their placement. These perturbations produce a systematic underestimation in the measured heat-pulse velocity (Cohen et al., 1981; Green and Clothier, 1988). Consequently, the heat-pulse velocity must be corrected for the probe-induced effects of wounding. This correction can be done empirically (e.g. Cohen et al.
At this point, we note that a priori the wound size is not known, although we might expect it to be a little larger than the size of the drill hole. This is because of additional damage which results from mechanical disruption of vessels at the edges of the drill hole. Anatomical investigations by Barrett et al. (1995) indicated the total wound width is likely to extend about 0.3 mm either side of the drill hole. Thus, a wound correction of (1.8 + 2× 0.3) mm seems appropriate for a drill hole of 1.
apple or kiwifruit, and so we have been able to use the same set of probes for periods of up to 3 months. In other species this may not be the case and then some reasoned assessment, or independent measure of transpiration, should be made to determine just how long the probes remain useful. 1.4 Converting Heat-Pulse Velocity to Sapflow Once the corrected heat-pulse velocity, Vc, has been determined, the next step is to relate it to the actual sap flow.
since the mass of air is negligible. The core sample is then immediately submerged in a beaker of water which has been placed on an accurate mass balance. The balance reading will indicate an immediate increase in mass, which equals the displacement of water, DT [kg]. The total volume, VT [m3], of the sample is then equal to ρL times DT, where the density of water, ρL, is assumed to be 1000 kg m3. The core sample is then oven-dried to determine the mass of dry wood, MD [kg].
in order to get the expression for the velocity profile as a function of stem radius, r [m]. This curve is then integrated over the sapwood cross-section to calculate the volume sap flux, Q, as R Q = ∫ 2πr J ( r ) dr (6) H for a stem of cambium radius R [m] and heartwood radius H [m].The stem parameter H needs to be determined from an analysis of trunk cores taken at the end of the experiment while R can be derived from the stem circumference and an allowance for the depth of the bark. 2.
output signals from the HPV unit should lie between ± 40 mV for the 1oC difference in temperature difference between the two sensors. The data logger is programmed to interpret the temperature signals and to record the subsequent ‘cross-over’ times which are used in Eq. (1) to calculate the raw heat-pulse velocity at a single point (depth) in the conducting sapwood. A laptop PC is later used to retrieve the tz data from the logger and to calculate total sap flow in the tree stem, as described by Eqs.
3.2. Connecting the HPV unit to the data logger: There are two leads which must to be connected to the HPV unit - a signal lead and a power lead. The pin-out of these leads is listed below.
4. Installing the heat-pulse probes. This section gives advice on how to install the heat-pulse probes into a plant stem. Note: It is good practice to test the operation of the logger and the probes, and to test all the wiring connections before inserting the probes into the plant stem. Although the HPV unit is designed to be operated automatically, the software does allow for a manual test of the system, as described later in the next section. 4.1.
this is the downstream probe (unmarked) e.g. the highest probe in the stem or the root probe nearest to the stem this is the heater probe this is the upstream probe (marked with a dot) Sap flow 4.2.3. Carefully drill the holes using a high-speed, electric drill. • Don’t drill too far at once (say more than 20mm) because this can 'over -bore' the hole. Make sure the hole is about 20 mm deeper than the longest probe. • Remove the jig and 'plug’ the holes with Vaseline.
ELSE swear a lot blame someone else (but not me) goto deep_shit ENDIF Note1: if you cant find deep_shit, then your not in it. Note2: There is no deep_shit. I expect that every thing will work Note3: Murphy’s Law suggests there will be some other problem to find. 5. Installing the data-logger software The following program is to be run on a Campbell data logger. The logger software is located in one of the three sub-directories on the disk provided with the installation. 5.1. Files in A:\LOGGER C10-HP*.
The following files have been supplied in the sub-directory A:\LOGGER of the installation disk: CR10-HP3.STN is the Station file required to communicate with the logger. CR10-HP3.DLD is a file to be 'downloaded’ to the logger, via the GT program. CR10-HP3.CSI is a file created by the program editor, EDLOG. The program CR10-HP3.DLD should be downloaded to the logger using the GT program (see Campbell PC208 manual for instructions on how to do this). 5.3.
5.5. Retrieving data from the logger Use the program PC208 to retrieve all the ‘uncollected’ data from the data logger. 5.6. Operation of the logger program - C10-HP3.DLD Here we describe a number of program changes and system tests that you may want to do. We also describe some 'normal' program behaviour that may be expected during the course of a measurement period.
5.6.5. To find out the total running-time since the heat-pulse was fired (loc. 99) enter *6 99 A enter *0 to continue 5.6.6. To change the duration of the heat pulse (alter Inst-44) enter *1 44 A A A x A *0 where x is duration in s default value is 2.0 s (this is also the maximum time) 5.6.7. To change the delay between firing a heat pulse and testing for a 'cross -over'. This may be necessary for really fast flows (alter Inst-49) enter *1 49 A A A x A *0 where x is delay in multiples of 0.
1: 99 Loc [ _________ ] 4: Volts (SE) (P1) 1: 12 Reps 2: 14 ñ 250 mV Fast Range 3: 1 SE Channel 4: 21 Loc [ _________ ] 5: 1 Mult 6: 0 Offset Measure current temp. signal and store in loc (21..32) Change as required 5: Beginning of Loop (P87) 1: 0 Delay 2: 12 Loop Count Check for cross-over times 6: IF (X<=>F) (P89) 1: 1 -- X Loc [ _________ ] 2: 1 = 3: 0 F 4: 30 Then Do Monitor loc (21..32) to observe temperature trace Change as required tz’s are stored in loc (1..
2: 30 Then Do 17: Do (P86) 1: 10 Set Output Flag High 18: Sample (P70) 1: 2 Reps 2: 91 Loc [ _________ ] Ouput the date and time 19: Sample (P70) 1: 12 Reps 2: 1 Loc [ _________ ] Output the 12 tz values Change as required 20: Do (P86) 1: 26 Set Flag 6 Low 21: Do (P86) 1: 25 Set Flag 5 Low 22: End (P95) 23: If Flag/Port (P91) 1: 11 Do if Flag 1 is High 2: 30 Then Do If Flag 1 is set then Initialise and reset arrays 24: Time (P18) 1: 2 Hours into current year (maximum 8748) 2: 8784 Mod/By 3: 91 Loc [
2: 60 3: 93 Mod/By Loc [ _________ ] 31: Z=X+Y (P33) 1: 92 X Loc [ _________ ] 2: 93 Y Loc [ _________ ] 3: 92 Z Loc [ _________ ] 32: Beginning of Loop (P87) 1: 0 Delay 2: 90 Loop Count Reset all storage arrays 33: Z=F (P30) 1: 0 F 2: 0 Exponent of 10 3: 1 -- Z Loc [ _________ ] 34: End (P95) 35: Volts (SE) (P1) 1: 12 Reps 2: 4 ñ 250 mV Slow Range 3: 1 SE Channel 4: 41 Loc [ _________ ] 5: 1 Mult 6: 0 Offset Measure initial temp signal and store in loc (41..
2: 3 3: 2 4: 31 >= F Exit Loop if True Change as required 45: End (P95) 46: Set Port(s) (P20) 1: 0 C8..C5 = 0/0/0/0 2: 0 C4..
The default time is 30 minutes 5.8.2. To fire a test heat-pulse enter *6 A D 1 (the lights should go on, and the program will run) enter *6 A D 6 for an early exit of program enter *0 to continue 5.8.3. To check if the system is working properly (generally a good idea!) fire a test heat pulse (see 5.8.2) check the initial voltages (+/- 20 mV is OK, -9999 is stuffed) i.e. enter *6 x A where x = 41..56 check the present voltages (+/- 100 mV is OK, -9999 is stuffed) i.e. enter *6 x A where x = 21..
enter *1 15 A A A x A where x is max time in multiples of 0.1s default value if 500 s, i.e. x=500, but 300s might be OK 5.9. Listing of the logger program - C21-HP4.CSI This section gives a listing of the CAPTURE program designed to measure the outputs generated by the HPV unit, and to calculate and store the tz’s associated with ea ch set of the probes. Note: For the program to run on a CR21X, the USER needs to enter the *A mode and reset the number of final output locations to 100.
16: End (P95) 3: 92 17: If Flag/Port (P91) 1: 16 Do if Flag 6 is High 2: 30 Then Do 31: Time (P18) 1: 1 Minutes into current day (max 1440) 2: 60 Mod/By 3: 93 Loc [ _________ ] 18: Do (P86) 1: 10 Set Output Flag High Z Loc [ _________ ] 32: Z=X+Y (P33) 1: 92 X Loc [ _________ ] 2: 93 Y Loc [ _________ ] 3: 92 Z Loc [ _________ ] 19: Sample (P70) 1: 2 Reps 2: 91 Loc [ _________ ] 33: Beginning of Loop (P87) 1: 0 Delay 2: 90 Loop Count 20: Sample (P70) 1: 16 Reps 2: 1 Loc [ _________ ] 34: Z=F (P30)
2: 3 Port Number 45: Set Port (P20) 1: 1 Set High 2: 4 Port Number 54: Beginning of Loop (P87) 1: 1 Delay 2: 0 Loop Count 46: Beginning of Loop (P87) 1: 1 Delay 2: 0 Loop Count 55: Timer (P26) 1: 99 Loc [ _________ ] 56: IF (X<=>F) (P89) 1: 99 X Loc [ _________ ] 2: 3 >= 3: 150 F 4: 15 Set Flag 5 High 47: Timer (P26) 1: 99 Loc [ _________ ] 48: IF (X<=>F) (P89) 1: 99 X Loc [ _________ ] 2: 3 >= 3: 20 F 4: 31 Exit Loop if True 57: If Flag/Port (P91) 1: 15 Do if Flag 5 is High 2: 31 Exit Loop if True
6. Running the ANALYSIS software ... (still under review) This section describes the software used to analyze the tz data collected by the data loggers. The analysis software is located in one of the four sub-directories on the disk provided with the installation. 6.1. Files in A:\FORT HPV-2000.FOR HPV-2000.EXE HPSAMPLE.DAT HPHEADER.DAT This subdirectory contains the FORTRAN programs required to analyze the heat-pulse data (HPV-2000.FOR and HPV-2000).
prob_depth1: prob_space1: prob_depth2: prob_space2: prob_depth3: prob_space3: Tmin,Tmax : Emax values: 0.50 1.00 0.50 1.00 0.50 1.00 185. 5.00 1.20 1.00 1.20 1.00 1.20 1.00 192. 5.00 2.20 1.00 2.20 1.00 2.20 1.00 3.50 1.00 3.50 1.00 3.50 1.00 5.00 The next example is the header-file required to analyze n=2 sets of probes: nprobes: 2 nsensors: 4 4 wound_width: 2.40 Swanson fac: 1 v-frac wood: 0.36 v-frac wat : 0.54 sapwood_rad: 6.21 hrtwood_rad: 0.00 prob_depth1: 0.50 prob_space1: 1.00 prob_depth2: 0.
where opid day hrmin tz1_* tz2_* = = = = = output identifier (103 ⇒ output from table 1, line 3) current day of year time when heat-pulse was fired tz times for probe 1 (*=1 is the outside depth) tz times for probe 2 (*=1 is the outside depth) Step - 3 Just keep appending new data to the bottom of the old input file 6.3. Examining the output file The analysis programme outputs three calculations of total sap flow, depending on how the volume sap flux, Q, is determined.
For well-behaved velocity profiles (i.e. small curvature at large radii) all three methods yield similar results, but for profiles where the curvature near the cambium method 3 is recommended (Hatton et al, 1990). 6.4. Listing of the ANALYSIS program The following is a listing of the FORTRAN program HPV-2000.FOR used to analyze the tz-data collected by the HPV data logger. The analysis procedure follows that outlined in the Background Section of this document.
* * 32, 36, 1.826, 2.090, 0.879, 0.818, 0.169, 0.221, 0.0, 0.0 / C------------------------------------------------------------c ... Set the wound corrections of Green and Clothier (1988) C------------------------------------------------------------DATA WC2/ 0, 0, 1, 0, 0.0, * 16, -0.171, 1.299, 0.0194, -0.000093, * 20, -0.159, 1.318, 0.0270, -0.000140, * 24, -0.135, 1.326, 0.0367, -0.000194, * 28, -0.143, 1.306, 0.0488, -0.000267, * 32, -0.067, 1.355, 0.0571, -0.000203, * 36, -0.013, 1.379, 0.
c ... vfwood = volume fraction of wood = 0.34 c ... vfwat = volume fraction of water = 0.56 C-----------------------------------------------------------WRITE(*,*) 'Enter the volume fraction of wood ' READ(30,1098) ANS,VFWOOD WRITE(*,*) 'Enter the volume fraction of water ' READ(30,1098) ANS,VFWAT C-----------------------------------------------------------c ...
ITOD = 1 IF(IDAY.GT.5) THEN IDAY = 1 TMIN = TMIN+5 TMAX = TMAX+5 CALL SETTEXTPOSITION(33 ,35,CURPOS) WRITE(*,*) '***** Click to CONTINUE *****' CALL MOUSECLICK(IX4,IY4) CALL CLEARSCREEN($GCLEARSCREEN) STATUS = SETCOLOR(8) STATUS = RECTANGLE($GFILLINTERIOR,0,0,NXPIX,NYPIX) STATUS = SETCOLOR(2) ENDIF ELSE ITOD = ITOD+1 ENDIF C-----------------------------------------------------------c ...
SAPFLOWV(J,ITOD) = FLUXV(J) SAPFLOWF(J,ITOD) = FLUXF(J) c GOTO 299 C-----------------------------------------------------------C ... compute sum of sap velocity times relative sapwood area C-----------------------------------------------------------R1P = SWR(J) R1M = (R(1)+R(2))/2. R2M = (R(2)+R(3))/2. R3M = (R(3)+R(4))/2.
SX3 = SX3 - SX*SX2/N SXY = SXY - SX*SY/N SX2Y= SX2Y- SX2*SY/N SX2 = SX2 - SX*SX/N D = SX2*SX4 - SX3**2 A1 = (SX4*SXY - SX3*SX2Y)/D A2 = (SX2*SX2Y - SX3*SXY)/D A0 = SY/N - A1*SX/N - A2*SSX2/N ELSE A0 = (Y(1)+Y(2))/2. A1=0.0 A2=0.
DO 10 I=1,NLINE READ(NUNIT,99) LINE IF(OP) WRITE( *,99) LINE CONTINUE FORMAT(A75) RETURN END SUBROUTINE INLINE 10 99 !========================================================== SUBROUTINE NEWONEPLOT(X1,Y1,NUM1,XTITLE, XUNIT, YTITLE, YUNIT & ,GX1MIN, GX1MAX, GY1MIN, GY1MAX, Y1LABEL, Y2LABEL ,LCOL) !========================================================== USE DFLIB IMPLICIT NONE TYPE (WINDOWCONFIG) WINC TYPE (QWINFO) QW INTEGER NUM1, NTICKX1, NTICKY1 INTEGER I, J,NXPIX, NYPIX, NC1, NC2 INTEGER IX,IY, ix4,
ENDIF IF(Y2LABEL) THEN CALL TITLEAXIS(1.15D0,0.5D0,YTITLEUNIT,1.4D0,1.4D0,NXPIX/1 & ,NYPIX,TALL,2) ! YAXIS TITLE CALL PLOTYTICK(1.0D0,Y1MIN, Y1MAX, Y1SCALE, NTICKY1,15, TALL & ,1.4D0,1.4D0,NXPIX/1, NYPIX) ENDIF STATUS = SETCOLOR(7) STATUS = RECTANGLE_W($GBORDER, 0.0D0,0.0D0,1.0D0,1.
REAL*8 XX(NUM), YY(NUM) LOGICAL STATUS TYPE (WXYCOORD) WXY 10 STATUS = SETCOLOR(LCOL) CALL MOVETO_W(XX(1), YY(1), WXY) DO 10 I=2,NUM STATUS = LINETO_W(XX(I), YY(I) ) CONTINUE RETURN END SUBROUTINE PLOTLINE C========================================================== SUBROUTINE PLOTXTICK(LOWX, HIGHX, XSCALE, NTICK, NCOL, & TALL, XW,YH, NXPIX,NYPIX, LOGPLOT) C========================================================== USE DFLIB IMPLICIT NONE TYPE (WXYCOORD) WXY REAL*8 LOWX, HIGHX, XSCALE, XRANGE, XTICK, DXTI
10 ELSE CALL NUMAXIS(XTICK+0.1,YTICK,YLABEL, XW,YH,NXPIX & , NYPIX,2, .FALSE.
C========================================================== IMPLICIT NONE REAL*8 HIGH, LOW, RANGE, DLHI, DLLO, DTICKS REAL*8 RPOW, RSCALE, RMAG, TEMP, TINY/1E-20/ INTEGER NTICKS, HELPSCALE ! ... find the range and magnitude and rescale if necessary RPOW = 0.0D0 RANGE = HIGH - LOW IF(LOW .EQ.0.0D0) LOW = TINY IF(HIGH.EQ.0.0D0) HIGH = 2.0d0*LOW IF(RANGE.EQ. 0.0D0) THEN ! THE LINE IS VERTICAL HIGH = HIGH + 0.5 LOW = LOW - 0.5 ENDIF DLHI = DLOG10(ABS(HIGH)) DLLO = DLOG10(ABS(LOW)) DO WHILE(DLHI.LT.0.0D0 .AND.
10 INTEGER I, NX REAL*8 X(NX), XMIN, XMAX XMIN = 1.0D10 XMAX = -1.0D10 DO 10 I=1,NX IF(X(I).LE.XMIN) XMIN = X(I) IF(X(I).GE.XMAX) XMAX = X(I) CONTINUE RETURN END SUBROUTINE RANGESET !========================================================== SUBROUTINE MOUSECLICK(X,Y) !========================================================== USE DFLIB IMPLICIT NONE INTEGER*4 MOUSEEVENT, KEYSTATE, X, Y, RESULT MOUSEEVENT = MOUSE$RBUTTONDOWN .OR.
7. References Barrett, D.J., Hatton, T.J., Ash, J.E., and Ball, M.C., 1995. Evaluation of the heat-pulse velocity technique for measurement of sap flow in rainforest and eucalypt forest species of south-eastern Australia. Plant Cell Environ., 18, 463-469. Cohen, Y., Fuchs, M., and Green, G.C., 1981. Inprovement of the heat-pulse method for determining sap flow in trees. Plant Cell Environ, 4, 391-397. Dye, P.J., Olbrich, B.W., and Poulter, A.G., 1991.
Appendix A – use of an AM25T multiplexer: Listing of logger programme to connect 3 heat-pulse units to a single CR10 data logger. Note: One AM25T could be used to measure up to 6 heat-pulse units, but this requires a small modification to the programme described below. Please email the author for details. CR10: AM25T +12 G C3 C2 no connection AG 1H 1L +12 G CLK RES EX AG HI LO (1H, 1L, 2H, 2L) (3H, 3L, 4H, 4L) (5H, 5L, 6H, 6L) (7H, 7L, 8H, 8L) and so on ...
1: 53 11: 1: 2: 3: 4: 5: 6: Set Port 3 Low Volt (SE) (P1) 2 Reps 15 2500 mV Fast Range 1 SE Channel 31 -- Loc [ _________ ] 1.0 Mult 0.0 Offset 12: Z=X-Y (P35) 1: 31 -- X Loc [ _________ ] 2: 61 -- Y Loc [ _________ ] 3: 31 -- Z Loc [ _________ ] 13: Calculate temperature difference and store in loc (31..54) End (P95) 14: Do (P86) 1: 52 Set Port 2 Low 15: Beginning of Loop (P87) 1: 0 Delay 2: 24 Loop Count 16: 1: 2: 3: 4: If (X<=>F) (P89) 1 -- X Loc [ _________ ] 1 = 0.
25: End (P95) 26: If Flag/Port (P91) ; Flag 6 is used to generate output 1: 16 Do if Flag 6 is High 2: 30 Then Do 27: Do (P86) 1: 10 Set Output Flag High 28: Sample (P70) 1: 2 Reps 2: 91 Loc [ _________ ] Output the date and time 29: Sample (P70) 1: 24 Reps 2: 1 Loc [ _________ ] Output the 24 tz values change as required 30: Do (P86) 1: 26 Set Flag 6 Low 31: Do (P86) 1: 25 Set Flag 5 Low 32: End (P95) 33: If Flag/Port (P91) ; Flag 1 begins the heat-pulse routine 1: 11 Do if Flag 1 is High 2: 30 The
41: Z=X+Y (P33) ; Store the time (hrmin) 1: 92 X Loc [ _________ ] 2: 93 Y Loc [ _________ ] 3: 92 Z Loc [ _________ ] (loc 92) 42: Beginning of Loop (P87) 1: 0 Delay 2: 90 Loop Count 43: Z=F (P30) ; Reset all storage arrays 1: 0 F 2: 0 Exponent of 10 3: 1 -- Z Loc [ _________ ] 44: End (P95) 45: Do (P86) 1: 42 Set Port 2 High ; measure initial voltage using AM25T ; Port 2 is connected reset of AM25T 46: Beginning of Loop (P87) 1: 0 Delay 2: 12 Loop Count ; for 4* N boxes 47: Step Loop Index (P90) 1
59: If Flag/Port (P91) 1: 12 Do if Flag 2 is High 2: 30 Then Do 60: Set Port(s) (P20) ; Port 1 (C1) is the heater control line 1: 0 C8..C5 = low/low/low/low 2: 1 C4..C1 = low/low/low/high 61: Beginning of Loop (P87) 1: 1 Delay 2: 0 Loop Count 62: Timer (P26) 1: 99 Loc [ _________ ] 63: 1: 2: 3: 4: 64: If (X<=>F) (P89) ; Fire the heater for 1 s 99 X Loc [ _________ ] 3 >= 1 F Change as required 31 Exit Loop if True End (P95) 65: Set Port(s) (P20) 1: 0 C8..C5 = low/low/low/low 2: 0 C4..
Appendix B – use of simple heat-pulse controller (no amplifiers) The heat-pulse controller and probes can be operated with most Campbell data loggers.
4: 5: 6: 7: 8: 1 100 21 1 0 Type T (Copper-Constantan) Ref Temp (Deg. C) Loc [ _________ ] Loc [ _________ ] Mult Offset 5: Beginning of Loop (P87) 1: 0 Delay 2: 8 Loop Count 6: 1: 2: 3: 4: If (X<=>F) (P89) ! loc 1..8 = Tz cross-over times 1 -- X Loc [ _________ ] 1 = 0 F 30 Then Do 7: 1: 2: 3: 4: If (X<=>Y) (P88) 41 -- X Loc [ _________ ] ! loc 41..48 = original temperature 3 >= 21 -- Y Loc [ _________ ] ! loc 21..
19: Sample (P70) ! output the cross-over times 1: 8 Reps 2: 1 Loc [ _________ ] 20: Do (P86) 1: 26 Set Flag 6 Low 21: Do (P86) 1: 25 Set Flag 5 Low 22: End (P95) 23: If Flag/Port (P91) 1: 11 Do if Flag 1 is High 2: 30 Then Do 24: Time (P18) 1: 2 Hours into current year (maximum 8784) 2: 8784 Mod/By 3: 91 Loc [ _________ ] ! store day of year 25: Z=X*F (P37) 1: 91 X Loc [ _________ ] 2: .
34: 35: 1: 2: 3: 4: 5: 6: 7: 8: End (P95) Thermocouple Temp (SE) (P13) ! measure initial temp difference 8 Reps 1 2.5 mV Slow Range 1 SE Channel 1 Type T (Copper-Constantan) 100 Ref Temp (Deg. C) Loc [ _________ ] 41 Loc [ _________ ] ! loc 41..
49: 1: 2: 3: 4: If (X<=>F) (P89) ! wait 10 s before making a Tz measure 99 X Loc [ _________ ] 3 >= 10 F ! change as required 15 Set Flag 5 High 50: If Flag/Port (P91) 1: 15 Do if Flag 5 is High 2: 31 Exit Loop if True 51: End (P95) 52: Do (P86) 1: 22 Set Flag 2 Low 53: End (P95) 54: Batt Voltage (P10) ! store battery voltage in loc 98 1: 98 Loc [ _________ ] *Table 2 Program 01: 0.0000 Execution Interval (seconds) *Table 3 Subroutines End Program *Table 2 Program 02: 0.
