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Calculations

You can define Calculation Tags to perform automatic processing of math formulas with any number of local or remote Tags as a data source. You can even use values directly from OPC Servers with the DirectOPC interface, and these OPC Items can also come from the local service or a remote service.

View the following video presentation on Calculations:

Direct link: https://www.openautomationsoftware.com/videos/#calculations

If you enable Security on a remote Service to disable all or selected Tags you will need to define the OAS Service User Name and Password under Configure Options, but also recommend to then enable Security to limit access of Read Tags under Configure-Security.

Functions

Following is a list of functions and their expected parameters.

ABS

Summary:

Returns absolute value.

Parameters:

Value to convert to absolute value

Internal code:

return Math.Abs(p[0].GetValueAsDouble());

 

ASCTOINT

Summary:

Converts ascii character to integer value.

Parameters:

Ascii character value to convert

Internal code:

Int32 testInteger;

string stringValue = p[0].GetValueAsString();

if (stringValue == null)

return 0;

if (stringValue.Length < 1)

return 0;

Char[] testChars;

testChars = stringValue.ToCharArray();

byte[] testBytes;

testBytes = Encoding.ASCII.GetBytes(testChars);

testInteger = testBytes[0];

return testInteger;

 

ASIN

Summary:

Returns the angle whose sine is the specified number.

Parameters:

A number representing a sine, where d must be greater than or equal to -1, but less than or equal to 1.

Internal code:

return Math.Asin(p[0].GetValueAsDouble());

 

ATAN

Summary:

Returns the angle whose tangent is the specified number.

Parameters:

A number representing a tangent.

Internal code:

return Math.Atan(p[0].GetValueAsDouble());

 

AVG

Summary:

Returns the moving average over a specified time period.

Parameters:

Tag value to evaluate in the moving average.

Time period to evaluate in seconds.

Internal code:

            Complex code using arrays of values and timestamps.

BCDINT

Summary:

Converts binary coded decimal to integer value.

Parameters:

BCD value to convert

Internal code:

double doublebcdvalue = p[0].GetValueAsDouble();

ulong bcdvalue = System.Convert.ToUInt64(doublebcdvalue);

string convertedString = bcdvalue.ToString(“X4”);

return System.Int32.Parse(convertedString);

BITC

Summary:

Bit compare of a specific bit postion of an integer value.

Parameters:

Integer value to evaluate

Bit position

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

ulong intVal = Convert.ToUInt64(Math.Floor(x));

int bitIndex = Convert.ToInt32(Math.Floor(y));

ulong shiftValue = 1;

ulong valueToCompare = shiftValue << bitIndex;

return (intVal & valueToCompare) > 0 ? 1 : 0;

 

BITSHIFTLEFT

Summary:

Bit shift left a specified number of bits of an integer value.

Parameters:

Integer value to evaluate

Number of bits to shift left

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

ulong intVal = Convert.ToUInt64(Math.Floor(x));

int bitIndex = Convert.ToInt32(Math.Floor(y));

return (intVal << bitIndex);

 

BITSHIFTRIGHT

Summary:

Bit shift right a specified number of bits of an integer value.

Parameters:

Integer value to evaluate

Number of bits to shift right

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

ulong intVal = Convert.ToUInt64(Math.Floor(x));

int bitIndex = Convert.ToInt32(Math.Floor(y));

return (intVal >> bitIndex);

 

BITWISEAND

Summary:

Bitwise AND of 2 integers.

Parameters:

Integer value to evaluate

Integer value to evaluate

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

ulong intVal = Convert.ToUInt64(Math.Floor(x));

ulong bitIndex = Convert.ToUInt64(Math.Floor(y));

return (intVal & bitIndex);

 

CEIL

Summary:

Ceiling of value.  Returns the smallest integral value that is greater than or equal to the specified double-precision floating-point number.

Parameters:

Value to evaluate

Internal code:

return Math.Ceiling(p[0].GetValueAsDouble());

 

CHR

Summary:

Returns a specific character within a string.

Parameters:

String value

Position of character within the string to return.

Internal code:

IConvertible o = p[0].GetValue();

IConvertible i = p[1].GetValue();

int index = Convert.ToInt32(i);

if(o is String)

{

return ((String)o)[index].ToString();

}

return Convert.ToString(o)[index].ToString();

 

CONCAT

Summary:

Concatenate strings together.

Parameters:

Strings to concatenate.

Internal code:

StringBuilder sb = new StringBuilder();

for(int i=0; i<p.Length; i++)

{

sb.Append(p[i].GetValueAsString());

}

return sb.ToString();

 

CONTAINS

Summary:

Returns true if string contains the second string parameter.

Parameters:

String to evaluate.

String to check for.

Internal code:

String temp = p[0].GetValueAsString();

String temp2 = p[1].GetValueAsString();

if (temp.Contains(temp2) )

return 1;

else

return 0;

 

COS

Summary:

Returns the cosine of the specified angle.

Parameters:

Value to convert.

Internal code:

return Math.Cos(p[0].GetValueAsDouble());

 

COSH

Summary:

Returns the hyperbolic cosine of the specified angle.

Parameters:

Value to convert.

Internal code:

double x__ = p[0].GetValueAsDouble();

return (Math.Exp(x__)+Math.Exp(-x__))*0.5;

 

COTAN

Summary:

Returns the cotangent of the specified angle.

Parameters:

An angle, measured in radians.

Internal code:

return 1/Math.Tan(p[0].GetValueAsDouble());

 

ENDSWITH

Summary:

Returns true if string ends with the second string parameter.

Parameters:

String to evaluate.

String to check for.

Internal code:

String temp = p[0].GetValueAsString();

String temp2 = p[1].GetValueAsString();

if (temp.EndsWith(temp2))

return 1;

else

return 0;

 

EXP

Summary:

Returns e raised to the specified power.

Parameters:

Value to convert.

Internal code:

return Math.Exp(p[0].GetValueAsDouble());

 

FLOOR

Summary:

Floor of value.  Returns the largest integer less than or equal to the specified double-precision floating-point number.

Parameters:

Value to convert

Internal code:

return Math.Floor(p[0].GetValueAsDouble());

 

HIGHBYTE

Summary:

Returns the high byte of a word.

Parameters:

Value to convert

Internal code:

double rawAsDouble = p[0].GetValueAsDouble();

UInt16 intVal = Convert.ToUInt16(rawAsDouble);

byte[] bytes = BitConverter.GetBytes(intVal);

if (BitConverter.IsLittleEndian)

return bytes[1];

else

return bytes[0];

 

HIGHWORD

Summary:

Returns the high word of an integer.

Parameters:

Value to convert

Internal code:

double rawAsDouble = p[0].GetValueAsDouble();

UInt32 intVal = Convert.ToUInt32(rawAsDouble);

byte[] bytes = BitConverter.GetBytes(intVal);

UInt16 tempWord;

if(BitConverter.IsLittleEndian)

tempWord = BitConverter.ToUInt16(bytes, 2);

else

tempWord = BitConverter.ToUInt16(bytes, 0);

return tempWord;

 

IF

Summary:

If, Then, Else.  Returns second parameter if first parameter is true, returns third parameter if first parameter is false.

Parameters:

Condition to evaluate

Value to return if condition is true

Value to return if condition is false

Internal code:

return (p[0].GetValueAsDouble()!=0.0) ? p[1].GetValue() : p[2].GetValue();

 

INDEXOF

Summary:

Returns position of first occurance of string to check for within the string to evaluate.

Parameters:

String to find index in

String to check for

Internal code:

String temp = p[0].GetValueAsString();

String temp2 = p[1].GetValueAsString();

Int32 firstIndex;

firstIndex = temp.IndexOf(temp2);

return firstIndex;

 

INTBCD

Summary:

Converts integer to binary coded decimal.

Parameters:

Integer value to convert

Internal code:

double doublebcdvalue = p[0].GetValueAsDouble();

ulong intvalue = System.Convert.ToUInt64(doublebcdvalue);

string convertedString = intvalue.ToString(“0”);

ulong returnvalue = System.Convert.ToUInt64(convertedString, 16);

return returnvalue;

 

INTPOW

Summary:

Returns a specified number raised to the specified power.

Parameters:

Value to be raised to a power.

The power.

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

return Math.Pow(x, Math.Floor(y));

 

INTTOASC

Summary:

Converts integer to ascii character value.

Parameters:

Integer value to convert

Internal code:

double doubleintvalue = p[0].GetValueAsDouble();

Int32 intvalue = System.Convert.ToInt32(doubleintvalue);

string testString;

Char testChar;

testChar = System.Convert.ToChar(intvalue);

testString = testChar.ToString();

return testString;

 

LN

Summary:

Returns the natural (base e) logarithm of a specified number.

Parameters:

Value to convert

Internal code:

return Math.Log(p[0].GetValueAsDouble());

 

LOG

Summary:

Returns the base 10 logarithm of a specified number.

Parameters:

Value to convert

Internal code:

return Math.Log(p[0].GetValueAsDouble())/Math.Log(10);

 

LOGN

Summary:

Returns the base logn of a specified number.

Parameters:

Value to convert

Internal code:

return Math.Log(p[0].GetValueAsDouble())/Math.Log(p[1].GetValueAsDouble());

 

LOWBYTE

Summary:

Returns the low byte of a word.

Parameters:

Value to convert

Internal code:

double rawAsDouble = p[0].GetValueAsDouble();

UInt16 intVal = Convert.ToUInt16(rawAsDouble);

byte[] bytes = BitConverter.GetBytes(intVal);

if (BitConverter.IsLittleEndian)

return bytes[0];

else

return bytes[1];

 

LOWWORD

Summary:

Returns the low word of an integer.

Parameters:

Value to convert

Internal code:

double rawAsDouble = p[0].GetValueAsDouble();

UInt32 intVal = Convert.ToUInt32(rawAsDouble);

byte[] bytes = BitConverter.GetBytes(intVal);

UInt16 tempWord;

if (BitConverter.IsLittleEndian)

tempWord = BitConverter.ToUInt16(bytes, 0);

else

tempWord = BitConverter.ToUInt16(bytes, 2);

return tempWord;

 

LTRIM

Summary:

Removes all leading occurrences spaces from a string.

Parameters:

String to convert.

Internal code:

IConvertible o = p[0].GetValue();

if(o is String)

{

return ((String)o).TrimStart();

}

return Convert.ToString(o).TrimStart();

 

MAX

Summary:

Returns highest value of 2 values.

Parameters:

First value to evaluate.

Second value to evaluate.

Internal code:

double x__ = p[0].GetValueAsDouble();

double y__ = p[1].GetValueAsDouble();

if (x__ > y__)

return x__;

else

return y__;

 

MEDIAN

Summary:

Returns median value from multiple values.  If an even number of values then it returns the average of the middle 2 numbers.

Parameters:

Each value to evaluate in the median calculation.

Internal code:

Complex

 

MIN

Summary:

Returns lowest value of 2 values.

Parameters:

First value to evaluate.

Second value to evaluate.

Internal code:

double x__ = p[0].GetValueAsDouble();

double y__ = p[1].GetValueAsDouble();

if (x__ < y__)

return x__;

else

return y__;

MOD

Summary:

Returns the modulus of parameter 1 with parameter 2 value applied.

Parameters:

Number to evaluate.

Operator.

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

int p1 = (int)Math.Floor(x);

int p2 = (int)Math.Floor(y);

return p1 % p2;

MOVMAX

Summary:

Returns the highest value over a specified time period.

Parameters:

Tag value to evaluate in the moving maximum.

Time period to evaluate in seconds.

Internal code:

Complex code using arrays of values and timestamps.

MOVMIN

Summary:

Returns the lowest value over a specified time period.

Parameters:

Tag value to evaluate in the moving minimum.

Time period to evaluate in seconds.

Internal code:

Complex code using arrays of values and timestamps.

 

MOVSUM

Summary:

Returns the total of all samples over a specified time period.

Parameters:

Tag value to evaluate in the moving summation.

Time period to evaluate in seconds.

Internal code:

Complex code using arrays of values and timestamps.

 

POW

Summary:

Returns a specified number raised to the specified power.

Parameters:

Number to be raised to  a power.

The power.

Internal code:

double x = p[0].GetValueAsDouble();

double y = p[1].GetValueAsDouble();

return Math.Pow(x, y);

 

REPLACE

Summary:

Returns a string with all occurrences matching the string value of parameter 2 replaced with the string value of parameter 3.

Parameters:

String to evaluate.

String to search for.

String to replace the occurrences found.

Internal code:

string stringValue = p[0].GetValueAsString();

string stringToCheck = p[1].GetValueAsString();

string stringToReplace = p[2].GetValueAsString();

return stringValue.Replace(stringToCheck, stringToReplace);

 

RND

Summary:

Returns a random number.

Parameters:

None.

Internal code:

if(random==null)

{

random = new Random();

}

return random.NextDouble();

RTRIM

Summary:

Removes all ending occurrences spaces from a string.

Parameters:

String to convert.

Internal code:

IConvertible o = p[0].GetValue();

if(o is String)

{

return ((String)o).TrimEnd();

}

return Convert.ToString(o).TrimEnd();

 

SIGN

Summary:

Returns 1 if value is greater than 0.  Returns -1 if less than 0.  Returns 0 if equal to 0.

Parameters:

Value to evaluate.

Internal code:

double x__= p[0].GetValueAsDouble();

if (x__ < 0)

return -1;

else

if (x__ > 0)

return 1.0;

else

return 0.0;

 

SIN

Summary:

Returns the sine of the specified angle.

Parameters:

An angle, measured in radians.

Internal code:

return Math.Sin(p[0].GetValueAsDouble());

 

SINH

Summary:

Returns the hyperbolic sine of the specified angle.

Parameters:

An angle, measured in radians.

Internal code:

double d = p[0].GetValueAsDouble();

return (Math.Exp(d)-Math.Exp(-d))*0.5;

 

SQR

Summary:

Returns the square of a specified number.

Parameters:

Value to convert.

Internal code:

double d = p[0].GetValueAsDouble();

return (d*d);

 

SQRT

Summary:

Returns the square root of a specified number.

Parameters:

Value to convert.

Internal code:

return Math.Sqrt(p[0].GetValueAsDouble());

 

STARTSWITH

Summary:

Returns true if string starts with the second string parameter.

Parameters:

String to evaluate.

String to check for.

Internal code:

String temp = p[0].GetValueAsString();

String temp2 = p[1].GetValueAsString();

if (temp.StartsWith(temp2))

return 1;

else

return 0;

 

STR

Summary:

Converts a number to a string.

Parameters:

Number to convert.

Internal code:

IConvertible o = p[0].GetValue();

if (o is String)

{

return o;

}

return Convert.ToString(o);

 

STRFORMT

Summary:

Converts a number to a string with the format of the second parameter.  For valid format codes search for .NET ToString Format.

Parameters:

Number to convert.

String containing format codes.

Internal code:

IConvertible o = p[0].GetValue();

string formatstring = p[1].GetValueAsString();

if (o is String)

{

return o;

}

else

{

double tempDouble = System.Convert.ToDouble(o);

return tempDouble.ToString(formatstring);

}

STRLEN

Summary:

Returns the length of a string.

Parameters:

String to evaluate.

Internal code:

String temp = p[0].GetValueAsString();

return Convert.ToDouble(temp.Length);

 

SUBSTR

Summary:

Returns a substring of a string.

Parameters:

String to evaluate.

Starting position within the string.

Length of string to return.

Internal code:

String s = p[0].GetValueAsString();

int start = (int)(p[1].GetValueAsDouble());

int length    =  (int)(p[2].GetValueAsDouble());

length = Math.Min(length, s.Length-start);

if (s == “0”)

return “0”;

return s.Substring(start,length);

 

SUM

Summary:

Summation of all values.

Parameters:

Values to sum.  As many parameters as you desire.

Internal code:

double total = 0;

for(int i=0; i<p.Length; i++)

{

total += p[i].GetValueAsDouble();

}

return total;

 

TAN

Summary:

Returns the tangent of the specified angle.

Parameters:

An angle, measured in radians.

Internal code:

return Math.Tan(p[0].GetValueAsDouble());

 

TRIM

Summary:

Removes all occurrences of spaces from a string.

Parameters:

String to convert.

Internal code:

IConvertible o = p[0].GetValue();

if(o is String)

{

return ((String)o).Trim();

}

return Convert.ToString(o).Trim();

 

TRUNC

Summary:

Truncates a value to the nearest integer.

Parameters:

Value to convert.

Internal code:

double x__ = p[0].GetValueAsDouble();

if (x__>=0)

{

return Math.Floor(x__);

}

else

{

return Math.Ceiling(x__);

}

 

UNIXTODATETIME

Summary:

Returns a string of the date and time with passing in the number of seconds since 1970.

Parameters:

Number of seconds since 1970.

String containing format codes.

Internal code:

double seconds = p[0].GetValueAsDouble();

string formatstring = p[1].GetValueAsString();

DateTime dt1970 = new DateTime(1970, 1, 1).AddSeconds(seconds);

return dt1970.ToString(formatstring);

 

VAL

Summary:

Converts a string to a number.

Parameters:

String to convert.

Internal code:

IConvertible o = p[0].GetValue();

if(o is String)

{

return Convert.ToDouble((String)o);

}

return Convert.ToDouble(o);

 

 

Following is a quick guide as an example to create a Calculation Tag.

Step 1

Using Configure-Tags create a new Tag with the name Total.

Select the local Service or the remote Service with the Ramp, Sine, and Random Tags.

Step 2

Select the new Total Tag and set the Data Source as Calculation.

Calculations 1

Step 3

Use the Edit Calculation button at the right to show the Calculation editor.

Calculations 2

Select the Insert Tag button and select Ramp.Value.

Calculations 3

Add a + symbol after [Ramp.Value] and insert the Tag Sine.Value.

Add a + symbol after [Sine.Value] and insert the Tag Random.Value.

The equation should now represent a total of all 3 Tags as the following:

[Ramp.Value]+[Sine.Value]+[Random.Value]

You can select OK and Apply Changes to then see the Total Tag value update to the total of all 3 Tags.

Refer to the Configure-Tags-Calculations section in the Open Automation Software Help file for descriptions of each Function for the Calculation engine.

Note: If any tag data source in a calculation is bad the resultant data quality for the calculation tag will also be bad unless you use the property Source When Bad.