Formulas, Functions and Variables

Probe for Windows can use variables, formulas, operators, functions and constants in various places...

Global formulas (ProbeMenu/Global formulas)
Readings screen (SitesMenu/Edit Keydata tab)
Export (export/report definition file FileMenu/Export)
Import (import definition file FileMenu/Import)
Lower and Upper Limits (ReadingsMenu/Scheduling Current State tab)
Site historical daily water use (ReadingsMenu/Scheduling Historical DWU tab)
Global daily water use (ReadingsMenu/Scheduling Historical DWU tab)
Graph reports (graph report definitions - see ProbeMenu/SystemOptions)
Graph scales (directly in the scale text box on graphs screen, reset scales; graph report definitions)
Schedule amounts How Schedule Amounts are calculated and used

Global formulas

Use: ProbeMenu/Global formulas

Global formulas and functions calculate results and variables that can be used anywhere else in Prwin - the values are global and available to all sites. For example...

Global Formula	Comment
`SHIRAZFAC = 0.25`	`SHIRAZFAC` can now be used in limit formulas
`BUDBURST = #12 December 2001#`	`BUDBURST` can be used to plot lines on graph reports

Readings screen

Use: SitesMenu/Edit Keydata tab

Formulas must start with a +, -, = or @. ~~and can be optionally followed by a colon (:) and the number of decimal places or a format code.~~

v3 Note: Individual entry of Name, Format and Formula

Examples...

Name	Format	Formula	Output	Comment
Cotton	`DWU`	`+COTTON.DWU`	3.2	Value from dwu file for each date in the readings screen, displayed in user selected dwu units. Can also be graphed
WaterUsed	`AMT`	`@CUM(EDWU)`	134	Accumulated daily water use over the season, giving total water through the plant, in mm.
Tension	`2`	`@LKV(CLAY.RTN,RZ1/70)`	56.32	Calculate the equivalent soil moisture tension from lookup file `CLAY.RTN`, display to 2 decimal places. but see functions

Upper and Lower Limits

Use: ReadingsMenu/Scheduling Current State tab

The upper and lower limit for irrigation scheduling is calculated from a formula.
The default formulas are UPPER: FULL, and LOWER: REFILL

Examples...

	Formula	Value	Comment
`LOWER`	`REFILL-20`	190	Set lower limit to 20 mm below refill
`UPPER`	`FULL-(FULL-REFILL)*0.5`	234	Set upper limit to 50% to refill
`LOWER`	`PWP+(FULL-PWP)*SHIRAZFAC`	175	Set lower limit to be between permanent wilting and full. Actual position set with global variable `SHIRAZFAC`
`LOWER`	`REFILL-(FULL-REFILL)*SHIRAZ.FAC`		Similar to above, but position factor read from season file `SHIRAZ.FAC`.

The upper and lower limits can be graphed.

Historical daily water use

Use: ReadingsMenu/Scheduling Historical DWU tab

There is a single global formula to calculate the current daily water use from historical data; and in addition each site can optionally have it's own formula. If the site formula is blank the global formula takes precedence.

The value of the site historical dwu is used...

As the suggested value of estimated dwu when posting irrigation's, rainfalls and readings; which the user can change.
When calculating the third predicted irrigation (GPIAMT and GPIDATE)

Examples...

Formula	Output	Comment
`4.3`	4.3 mm/day	Always 4.3 mm/day
`COTTON.DWU`	2.3 mm/day	Current value from this dwu file
`COTTON.DWU * 1.2`	2.8 mm/day	Increase value by 20%

Print Reports and Export

Use: FileMenu/Export

Each line in the report definition file will print some data from a source (or calculated from a formula) at a nominated position on the paper - see page 59 for a full description.

Examples of formulas

Formula	Output	Comment
`EDWU`	2.3 mm/day	Estimated daily water use
`EPIAMT`	132	Amount in mm that needs to be applied at the scheduled irrigation
`EPIAMTAREAFACTOR2`	2.3 mm/day	Amount required in Kl, multiplied by site factor as set on ReadingsMenu/Scheduling delivery tab
`DELIVIRRIAREA10`	2,345 Kl	Total amount delivered in kl
`WATERTIME/WATERVOL`	2,345 Kl/day	Delivery rate
`24DELIVIRRIWATERTIMEAREA10/WATERVOL`	145 hrs	Total amount delivered in hours

The output can be scaled depending on the units selected by the user with ProbeMenu/DisplayUnits.

Report output can be restricted with a where clause - for example...

Where Clause	Comment
`EPIDATE < (TODAY+3)`	Only output scheduled irrigation's due in the next 3 days
`CRNTAMT< (REFILL+20)`	Only output sites that are within 20 mm of the refill point

Graph reports

Use: ProbeMenu/SystemOptionsreport definition tab to edit the GPT file

Each line in the gpt file can print data from a source (or calculated from a formula) at a nominated position on the paper, or plot boxes, lines and arrows - see page 23 for a full description.

Formulas are similar to export.

Some examples of formulas to plot lines and arrows

X1	X2	Y1	Y2	Type	Comment
`80`	`20`	`95`	`40`	`BOX`	Plot box from 80,20 to 95,40
`80`	`20`	`CRNTDATE`	`CRNTAMT`	`LINE`	Plot line from 80,20 on paper to last probe readings
`PREVDATE`	`PREVAMT`	`PREVDATE`	`PREVAMT+10`	`ARROW`	vertical arrow pointing at last probe reading
`BUDBURST`	`BUDBURST`	`TYMIN`	`TYMAX`	`LINE`	Line at BUDBURST date (as set on global formulas), the full height of the time graph

Graph Scales

The scales for a graph can be entered as a fixed number (e.g. 20 or 1/1/2001), or as a formula.
Scales can be entered...

Directly on the graph screen (in the scale text boxes)
As the 'reset' value on GraphMenu/Options Reset tab
In a graph report definition file using ProbeMenu/SystemOptions report definitions tab.

Reset scales are only used when the user clicks the <reset> button on the graph screen.

Scales set in a graph report definition overide the value entered by the user on the screen

Some examples

Formula	Result	Comment
`FULL+20`	235	Sets the vertical scale to be full point + 20
`CRNTDATE+10`	1/2/2001	Set the date axis to be last date in the readings screen plus 10 days. If this is the reset formula the time graph will 'stretch' each time `<reset>` is used.
`PDATE-10`	20/9/2000	Set the date axis to be 10 days before planting date (as set for each site on SitesMenu/Edit).

Variables

The following variables can be used in formulas and function for export, import and graph report definitions.

Variable	Comment	Units
`TODAY`	Today's date	date
`NOW`	Today, now (includes time)	date
`NULL`	Empty (used in `@IF()`)
`LXA`	Constant to calculate Volume `Volume = Area * Depth *LXA ( = 10)`
`SITE`	Site number
`NAME`	Name of site
`SELECTED`	Site is 'selected'
`YEAR`	Season number
`FARM`	Farm number
`CROP`	Name of crop
`CropNum`	ID number of crop (v3)
`MethodID`	Irrigation method. 0=cyclic,1=spare,2=drip/continuous (v3)
`AREA`	Area	Ha
`POSITION`	Position of tube (0-100)
`WATERTIME`	Total water delivery time (days and fraction)	days
`WATERVOL`	Total delivered volume Note: DeliverRate=WATERVOL/(WATERTIME *24)(Kl/Hr)	Kl
`LIRRDATE`	Date of last irrigation	date
`LIRRAMT`	RZ1 amount after last irrigation	mm
`REFILL`	Refill point	mm
`FULL`	Full point	mm
`LPRBDATE`	Date of last probe reading	date
`LPRBAMT`	RZ1 at last probe reading	mm
`PROBEDWU`	Latest probe dwu	mm/day
`PPIDATE`	Predicted date based on pdwu	date
`PPIAMT`	Amount to be delivered	mm
`ESTDWU`	Latest estimated dwu	mm/day
`EPIDATE`	Predicted date based on edwu	date
`EPIAMT`	Amount to be delivered	mm
`SITEGDWU`	Formula for site historical dwu	text
`GPIDATE`	Predicted date based on sitegdwu	date
`GPIAMT`	Amount to be delivered	mm
`CRNTAMT`	Rz1 value in latest column	mm
`CRNTDATE`	Date in latest column (but see DATE_LASTP)	date
`PDATE`	Planting date	date
`PWP`	Permanent wilting point	mm
`PREVAMT`	RZ1 at previous probe readings	mm
`PREVDATE`	Date of previous probe reading	date
`DELIVIRRI`	Total delivered irrigations	mm
`EFFIRRI`	Total effective irrigations	mm
`DELIVRAIN`	Total delivered rain	mm
`EFFRAIN`	Total effective rains	mm
`NUMIRRI`	Number of irrigations
`NUMRAIN`	Number of rains
`UPPER`	Formula for upper limit	text
`LOWER`	Formula for lower limit	text
`UPPERAMT`	Value of UPPER formula at CRNTDATE	mm
`LOWERAMT`	Value of LOWER formula at CRNTDATE	mm
`SUPPERAMT`	Value of UPPER formula at next scheduled irrigation date	mm
`SLOWERRAMT`	Value of LOWER formula at next scheduled irrigation date	mm
`FACTOR2`	Delivery factor	numeric
`COMMENT`	Comment for grower about site	text
`XCOORD`	GPS coordinate (not used)
`YCOORD`	GPS coordinate (not used)
`RZTEXT1`	Root zone 1 definition eg 0-70cm	text
`RZTEXT2`	Root zone 2 definition eg 25-70cm	text
`RZTEXT3`	Root zone 3 definition eg 90-130cm	text
`RZAMT2`	Latest root zone 2 amount	mm
`RZAMT3`	Latest root zone 3 amount	mm
`RZ1START`	Value of RZ1 at first reading of season (v3, v1 1.0.232->)	mm
`RZ1Top`	Value of top of Root Zone (eg: 20 for 0-70cm) (v3)	cm
`RZ1Bottom`	Value of bottom of Root Zone 1 (eg: 70 for 0-70cm) (v3)	cm
`LIRRDAMT`	Last irrigation delivered amount.	mm
`LIRREAMT`	Last irrigation effective amount.	mm
`LIRRDRAIN`	Total delivered rain since last irrigation.	mm
`LIRRERAIN`	Total effective rain since last irrigation.	mm
`ROWSPACE`	Row spacing	cm
`EMITSPACE`	Emitter spacing	cm
`EMITRATE`	Emitter rate	litre/hour
`DRIPDAYS`	Number of days over which drip volumes calculated Amount = DRIPDAYS * DWU	days
`RDIFACTOR`	Formula that evaluates to a Crop Factor (Kc) value. ActualAmount = DRIPDAYS * DWU * RDIFACTOR	text
`PLANTSPACE`	Spacing between plants	cm
`WETWIDTH`	Width of wetted zone. If value=0 assume wetted over entire area	cm
New for ver 3...
`DATE1`	Critical date 1 (e.g. 'Bud burst') date entered on: SitesMenu/Edit text (eg Bud burst) on: ProbeMenu/Crops	date
`DATE2`	Critical date 2	date
`DATE3`	Critical date 3	date
`DATE4`	Critical date 4	date
`DATE5`	Critical date 5	date
`DATE6`	Critical date 6	date
`KSOILFILE`	name of file with dwu correction factors depending water content realative to refill/full
`SCHEDULEDWU`	Value of CDWU used to calculate 'scheduled' irrigation Average Crop Daily Water Use (CDWU) in next 7 days (DripDays)	mm/day
`SCHEDULEAMT`	Amount required using schedule DWU Continuous: mm required to reach target in 7 days Cyclic: UPPER - STRESS (stress= LOWER or REFILL, depending on CropType)	mm
`SCHEDULEDATE`	Date of irrigation using schedule DWU Continuous: date 7 (DripDays) days ahead Cyclic: date hit stress (either LOWER or REFILL, depending on CropType)	date
`KEY1 KEY2` etc	Value of keydata row 1 in last column also KEY2, KEY3,...KEY16	numeric
`SITEREPORT`	Name of site specific report (v3)
`SEASONEND`	Value of RZ1 at first reading of season (v3)
`ALLOCATIONVOL`	Total volume needed for entire season	kL
`SUPPERAMT`	Upper (full) RZ1 amount used for scheduling (v3)	mm
`SLOWERAMT`	Lower (refill) RZ1 amount used for scheduling (v3)	mm
Any value on the readings screen can used (v3)
The row and column need to specified eg `K3_FULL` will give the value of K3 in the FULL column
Specify the row with...
`DATE`	date row
`TYPE`	Type row
`R1 - R16`	a VSW row
`RZ1, RZ2, RZ3`	an RZ row
`PDWU`	Probe DWU row
`EDWU`	Estimated DWU row
`DEFICIT`	the deficit row
`K1 - K16`	a KeyData row
Specify the column with...
`FULL`	FULL (or maximum) column
`REFILL`	REFILL (or minimum) column
`PWP`	PWP column
`C1, C2...`	by number eg `C1` = column 1
`FIRSTP`	the first probe reading
`LASTP`	the last probe reading
`PREVP`	the reading before the last reading
`PREVIOUSP`	the reading before the current column
`Previous`	the previous column (reading, estimate or gain)
Examples...
`R1_FULL`	Value of FULL VSW % at depth 1	%
`KEY1_LASTP`	Value of `K1` at the latest probe reading
`DATE_LASTP`	The date of the last probe reading (but see CRNTDATE)
`RZ1_PREVP`	Last week's `RZ1` value	mm
`RZ3_FIRSTP`	Value of `RZ3` from first probe reading of the season - week 1	mm
`RZ1_LASTP - RZ1_FIRSTP`	Change in RZ1 over the whole season	mm
`K3_PREVIOUS`	Value of `K3` in previous week
`K3 - K3_PREVIOUS`	Change in value of `K3`
`DATE_FULL`	The date the FULL readings were read>
Predicted values - see ReadingsMenu/Scheduling (v3)
	These values are calculated for each site, but not saved in [SITES] table. The period will start from the last date on readings screen The number of days (eg 7) set for each site.
`PredictedRain`	Total predicted rain eg 3.8724
`PredictedRain_T`	as above, but formatted eg 3.8 mm '-' if forecast location has not been set
`PredictedET`	Average ET in this period eg 12.372	mm/day
`PredictedET_T`	as above, but in text eg 12.4 mm/day
`PredictedKc`	Average Kcrop (Kc) in the period eg 0.3729	factor
`PredictedKC_T`	as above, but formatted eg 0.37
`PredictedKs`	Average Ksoil (Ks) in the period eg 0.8724	mm/day
`PredictedKs_T`	as above, but formatted eg 0.87
`PredictedDWU`	Average soil depletion rate eg 2.8724	mm/day
`PredictedDWU_T`	as above, but formatted eg 2.9 mm/day
Forecast values - see ProbeMenu/Forecast (v3)
	Only available if a Weather location has been set for the site, and the location has Rain and ET active The period will start today The number of days (eg 7), and Total or Average is set on ProbeMenu/Forecast tab: values
`ForecastRain`	Rain in next 7 days eg 12.372	mm
`ForecastRain_T`	as above, but formatted eg 12.4 mm
`ForecastET`	Average et/day in next 7 days eg 3.56	mm
`ForecastET_T`	as above, but formatted eg 12.4 mm
All below entered on FarmsMenu/Edit
`FARMNAME`
`FARMOWNER`
`ADDRESS1`
`ADDRESS2`
`TOWN`
`POSTCODE`
`COUNTRY`
`TEL`
`TEL2`
`FAX`
`MOBILE`
`EMAIL`
All below entered on FileMenu/Register
`OWNER1`	normally Company name
`OWNER2`	normally Address
... (1-10)

Notes:

Dates are in 'days-since-Jan1 1900', and need formatting using Microsoft standard format codes (e.g. d mmm yyyy)
Variables printed with the special format codes DWU, AMT, VOL, AREA, DEPTH, VSW, EMITRATE will be automatically converted to the 'user units' as set on ProbeMenu/DisplayUnits

Version 1 and 2

Available in version 3

Graphs reports only

(T = time graph; use D for depth graph)

Variable	Value returned
`TXMIN`	Minimum value on horizontal axis
`TXMAX`	Maximum value on horizontal axis
`TYMIN`	Minimum value on vertical axis
`TYMAX`	Maximum value on vertical axis
`TLEFT`	Left edge of graph (% paper)
`TRIGHT`	Right edge of graph (% paper)
`TTOP`	Top edge of graph (% paper)
`TBOTTOM`	Bottom of graph (% paper)
`TXLEG`	Horizontal position of legend (% paper)
`TYLEG`	Vertical position of legend (% paper)

Export only

Variable	Value returned
`SORT`	Sort order
`WHERE`	Where criteria
`FILE`	Name of file used for export
`PAGE`	Current page number
`Cn`	Value of column n in report
`JOIN`	Name of lookup file
`Ln`	Value from column n in lookup file
`LName`	Value for named field LName in lookup file
`UDWU`	Text of dwu units e.g. ins/day
`FDWU`	Factor to convert to user units of dwu e.g. UserValue = EDWU/FDWU returns in ins/day
`UVOL`	Text of dwu units e.g. AcreFt
`FVOL`	Factor to convert to user units of volume e.g. UserValue = AREA*EPIAMT/FAREA returns in AcreFt
`UAMT`	Text of amount units e.g. ins
`FAMT`	Factor to convert to user units of amounts of water e.g. UserValue = EPIAMT/FAMT returns in ins
`UAREA`	Text of dwu units e.g. mm/day
`FAREA`	Factor to convert to user units of area e.g. UserValue = AREA/FAREA returns in acres
`UDEPTH`	Text of depth units e.g. ft
`FDEPTH`	Factor to convert to user units of area e.g. UserValue = AREA/FDEPTH returns in ft
`UVSW`	Text of volumetric soil water units e.g. ins/ft
`FVSW`	Factor to convert to user units of VSW e.g. UserValue = R1/FVSW returns in ins/ft
`UEMITRATE`	Text of emitter rate units e.g. gal/hour
`FEMITRATE`	Factor to convert to user units of emitter rate e.g. UserValue = EMITRATE/FEMITRATE returns in gal/hour

Import only

Variable	Value returned
`Cn`	Value from column n in import file
`LASTDATE`	Last date in current readings
`LOADSITE`	Used to load and post to a site

Readings Screen only

Entered on SiteMenu/Edit

Variable	Value returned
`DATE`	date of column
`TYPE`	Type of column
`Rn`	VSW row n. Eg R1 = row 1
`SN`	Serial number
`RZn`	Root zone n Eg RZ1 = root zone 1
`PDWU`	Probe daily water use
`EDWU`	Estimated daily water use
`Deficit`	Full - current RZ1 value
`Kn`	Keydata row `n` Eg K1 = keydata row 1

Functions

The following functions are available.

Function	Comments	Used...	Example
`@DATESERIAL(Y,M,D)`	Y=Year M=Month D=Day	Export, Import	`@DATE(\C2,\C3,\C4)`
`@TIMESERIAL(H,M,S)`	H=Hour M=Minute S=Second	Export, Import	`@TIME(\C5,\C6)`
`@DOY(Date)`	Day of year since Jan 1	Export, Readings	`@DOY(PPIDATE)`
`@LKV(File)`	Looks up corresponding value in a file	Export, Import, Readings	`@LKV(CLAY.RTN, RZ1/70)`v1
`@LKV(Value, Filename, Style, ColIn, ColOut, Headers)`	Looks up corresponding value in file Value - name of variable that is being looked for in the file eg `DATE` Filename - the file must be in `shared\` folder Style... 0 = Interpolate between two values 1 = use Value just less than passed value 2 = use Value just greater than passed value ColIN (optional, default=1) column in table with value ColOUT(optional, default=2) column in file with the result Number of header lines (optional, default=0)	Export, Import, Readings	`@LKV(Date, blenheim.et, 0, 1, 2, 1)` v3 0 = style = interpolate 1 = Value column 2 = Result column 1 = 1 heading (skipped)
`@IF(Test,Value1,Value2)`	If 'test' is true return 'value1', else return 'value2'	Export, Import, Readings	`@IF(TYPE=21,RZ1,NULL)`
`@MAX(Value1, Value2)`	Maximum of Value1 or Value2	any	`@Max(RZ1, FULL)` v3
`@MIN(Value1, Value2)`	Maximum of Value1 or Value2	any	v3
`@RATE(Item)`	Rate of change of ‘item’ eg fruit size growth rate rate = (Value - PreviousValue) / (Date - PreviousDate)	Readings	`@RATE(SIZE)`
`@DIFF(Item)`	Difference between values e.g. water used between readings from water meter readings diff = Value - PreviousValue	Readings	`@DIFF(WaterMeter)`
`@ADD(Item)`	Addition of succesive values e.g. ?? Add = (Value + PreviousValue) also see period	Readings	`@ADD(K3)`
`@AVG(Item)`	Average of previous e.g. ?? Average = (Value + PreviousValue)/2 also see period	Readings	`@AVG(FruitCount)`
`@ACC(Item)`	Running total e.g. running total of rain during season SeasonTotal = SeasonTotal + Value Acc = SeasonTotal	Readings	`@ACC(DeliveredRain)`
`@CUM(item)`	Accumulate dwu - total water used by crop SeasonTotal = SeasonTotal + Value * (Date - PreviousDate) cum = SeasonTotal	Readings	`@CUM(EDWU)`
`@SM(item, factor)`	Smooth item using a Factor sm = (Factor * Value) + ((1 - Factor) * PreviousValue) fruit size in `K1` factor = eg `0.1`	Readings	`@SM(K1, 0.1)`
`@AVG(item, days)`	The calculation period (eg 30 days) can be specified for `@ADD(),@AVG()`		`@AVG(SIZE, 30)`
`@PI()`	3.14159...	any	`@PI() * 200 * 200` v3
`@ABS(Value)`	Result is always positive	any	`@ABS(PDWU)` v3
`@INT(Value)`	Whole number, truncated	any	`@INT(RZ1)` v3
`@FIX(Value)`	Same as INT(), unless Value is negative (phone..)	any	v3
`@SGN(Value)`	If Value > zero returns `+1` If value = zero returns `0` If Value < zero returns `-1`	any	v3
`@SQR(Value)`	Square root of Value	any	v3
`@LOG(Value)`	Log(Value) to base e: Log10 = Log(Value)/Log(10)	any	v3
`@EXP(Value)`	e ^ Value (e=2.718)	any	v3
`@SIN(Value)`	Value in radians	any	v3
`@COS(Value)`	Value in radians	any	v3
`@TAN(Value)`	Value in radians	any	v3
`@ATAN(Value)`	Value in radians	any	v3

Notes:

LKV()looks up data in a lookup text file. For example...
@LKV(CLAY.RTN,RZ1/70)

RZ1/70 calculates the average VSW in root zone 1 (assuming it is set to be from 0-70 cm), so this formula will calculate the equivalent soil suction using values file CLAY.RTN.

This could also be used to calculate sap pressure from soil moisture.

Constants

Constants such as COTTON.DWU * 1.2 can be used.

Date constants must be enclosed in # #. For example, a criteria for a report to only output irrigations scheduled before 1 June...

EPIDATE < #1 June 2000#

Operators

+	Add
-	Subtract
*	Multiply
/	Divide
AND	logical AND
OR	logical OR
XOR	phone

Calculation of Irrigation Scheduled amounts

UPPERAMT, LOWERAMT are calculated from UPPER and LOWER formulas

'RDICorrection' is calculated from RDIFACTOR

EffectiveAmountRequired(mm) = UPPERAMT - LOWERAMT or DWU * DRIPDAYS * RDICorrection

Calculated amount left in variables EPIAMT, PPIAMT, GPIAMT.

So 'DeliverAmountRequired(mm)' = FACTOR2 * EPIAMT

V2 Note: SCHEDULEAMT uses 'schedule with', and is either... (EPIAMT or PPIAMT or GPIAMT) * FACTOR2)

So 'ScheduleAmountRequired(mm)' = SCHEDULEAMT (FACTOR2 is already included)

If these intermediate values are calculated...

WetArea = AREA * ( WETWIDTH / PLANTSPACE )

PumpRate = WATERVOL * WATERTIME

The formulas in GPT, RPT or SPT files...

Caption	Formula	Format code
DeliveredAmount(Vol) using EDWU	`FACTOR2 * EPIAMT * WetArea * 10`	VOL
DeliveredAmount(Hours) using EDWU	`FACTOR2 * EPIAMT * WetArea * 10 / PumpRate`	LONGTIME
DeliveredAmount(Vol) using 'Schedule with'	`SCHEDULEAMT * WetArea * 10`	VOL
DeliveredAmount(Hours) using 'Schedule with'	`SCHEDULEAMT * WetArea * 10 / PumpRate`	LONGTIME