 # Expressions Expressions are used in Smart Rules “Equation” and “Formula”.
Extra functions can be used on Modbus devices to read/write values from/to Modbus registers.

## Mathematical expressions

### +, -, *, /

`(20.5 + 9.5) / 2    (15)`

## Logical expressions

### AND, OR, !, =, !=, >, <

```(!IsRaining OR (Wind>30))
MultiValueSwitchState != 2 (Not equal to 2)```

## Functions

### IF

`IF(logical_expression, value_if_true, value_if_false)`

Returns one value if a logical expression is ‘TRUE’ and another if it is ‘FALSE’.

### LINEAR

Returns linearly adjusted value – linear interpolation.

LINEAR(input, value1_input, value1_output, value2_input, value2_output)

```Example 1: LINEAR(250,  0,0,  50,500)   (Result is 25°C)

Example 2: LINEAR(Co2,  400,0,  1200,1)
(If value from Co2 sensor is 400ppm, output for air recovery will be 0%.
If Co2 is 1200, output will be 100%. And if e.g. Co2=800, output will be 50%)```

### LINEAR (BOUNDS)

An extension of the LINEAR function. It linearly interpolates an input value. If the input value is outside the defined range output value will be one of the extrema (minimum or maximum).

`LINEAR(input, value1_input, value1_output, value2_input, value2_output, BOUNDS)`

Examples:

• LINEAR(110, 100, 0, 0, 1, BOUNDS) → 0.0

• LINEAR(110, 0, 0, 100, 1, BOUNDS) → 1.0

### LINEAR (STRICT)

An extension of the LINEAR function. It linearly interpolates an input value. The input value must be within the defined range. If the input value is outside the defined range output value will be NaN (not a number) value.

`LINEAR(input, value1_input, value1_output, value2_input, value2_output, STRICT)`

Examples:

• LINEAR(110, 100, 0, 0, 1, STRICT) → NaN

• LINEAR(110, 0, 0, 100, 1, STRICT) → NaN

### SWITCH

`SWITCH(expression, case1, value1, [case2, ...], [value2, ...], default_value)`

Tests an expression against a list of cases and returns the corresponding value of the first matching case, with a default value if nothing else is met.

Example  Configuration ReadState ... SWITCH(MODBUSR(H, 168, UInt16),   0, 0,   0x02, 1,   0x04, 2,   0x08, 3,   0x10, 4,   0x40, 5, 0x800, 6,   0)
WriteState ... MODBUSWNE(H, 168, UInt16, SWITCH(Mu,   0, 0,   1, 0x02,   2, 0x04,   3, 0x08,   4, 0x10,  5, 0x40,   6, 0x800,  0)

Result ### MIN

`MIN(value1, value2)`

Returns the smaller of the two values.

### MAX

`MAX(value1, value)`

Returns the larger of the two values.

### ROUND

`ROUND(value1)    `

Returns the rounded value.

`Example 1: ROUND(2.01) (Result is 2)`

`Example 2: ROUND(2.49) (Result is 2)`

`Example 3: ROUND(2.5) (Result is 3)`

`Example 4: ROUND(2.99) (Result is 3)`

Core 2018.1.9623

### DEWPOINT

```DEWPOINT(temperature, relativeHumidity)
Returns the dew point temperature given the current temperature and relative humidity. Dew point is calculated according to this equation:http://bmcnoldy.rsmas.miami.edu/Humidity.html. ```

`Example 1: DEWPOINT(20, 50) (Result is ~9.26)`

`Example 2: DEWPOINT(0, 100) (Result is 0)`

Core 2018.1.9623

### POWER

Core 2021.1

The POWER function calculates a given number, raised to a supplied power.

`POWER(number, power)`

Examples:

• POWER(2,3) … 2^3 = 8

• POWER(10, -3) … 0,001

• POWER(25, 0) … 1

### MOD

Core 2021.1

The MOD function returns the remainder of a division between two supplied numbers.

`MOD(number, divisor)`

Arguments:

• number - The number to be divided.

• divisor - The value that the number argument is divided by.

Examples:

• MOD(6, 4)  … 2

• MOD(6, 2.5) … 1

### CEIL

Core 2021.1

The CEIL function rounds a supplied number away from zero, to the nearest multiple of a given number.

`CEIL(number, significance)`

Arguments:

• number   - The number that is to be rounded.

• significance (optional) - The multiple of significance that the supplied number should be rounded to. If the significance is not specified, then it is equal to 1.
(This should generally have the same arithmetic sign (positive or negative) as the supplied number argument)

Examples:

• CEIL(22.25,0.1) … 22.3

• CEIL(22.25,1) … 23

• CEIL(22.25) … 23

• CEIL(-22.25,-1) … -23

• CEIL(-22.25,1) … -22

• CEIL(-22.25) … -22

• CEIL(-22.25,-5) … -25

### FLOOR

Core 2021.1

The FLOOR function rounds a supplied number towards zero to the nearest multiple of a specified significance.

`FLOOR(number, significance)`

Arguments:

• number - The number that is to be rounded.

• significance (optional) -The multiple of significance that the supplied number is to be rounded to. If the significance is not specified, then it is equal to 1.
(This should generally have the same arithmetic sign (positive or negative) as the supplied number argument)

Examples:

• FLOOR(22.25,0.1)… 22.2

• FLOOR(22.25,1) … 22

• FLOOR(22.25) … 22

• FLOOR(-22.25,-1) … -22

• FLOOR(-22.25,1) … -23

• FLOOR(-22.25) … -23

• FLOOR(-22.25,-5) … -20

### RAND

Core 2021.1

The Rand function generates a random real number between 0 and 1.

`RAND()`

Examples:

• RAND()

### RANDINT

Core 2021.1

The RANDINT function generates a random integer between two supplied integers.

`RANDINT(bottom, top)`

Examples:

• RANDINT(1,5)

• RANDINT(-2,2)

### SIGN

Core 2021.1

The SIGN function returns the arithmetic sign (+1, -1 or 0) of a supplied number. I.e. if the number is positive, the SIGN function returns +1, if the number is negative, the function returns -1 and if the number is 0 (zero), the function returns 0.

`SIGN(number)`

Examples:

• SIGN(100) … 1

• SIGN(0) … 0

• SIGN(-100) … -1

### SQRT

Core 2021.1

The SQRT function calculates the positive square root of a supplied number.

`SQRT(number)`

Examples:

• SQRT(25) … 5

### LOG

Core 2021.1

The LOG function calculates the logarithm of a given number, to a supplied base.

`LOG(number, base)`

Arguments:

• number - The positive real number that you want to calculate the logarithm of.

• base (optional) - An optional argument that specifies the base to which the logarithm should be calculated.
If the argument is not specified, then the base argument uses the default value 10.

Examples:

• LOG(4,0.5) … -2

• LOG(100) … 2

### LN

Core 2021.1

The LN function calculates the natural logarithm of a given number.

`LN(number)`

where the number argument is the positive real number that you want to calculate the natural logarithm of.

Examples:

• LN(100) … 4,60517

## Bit operations

### GETBIT

Returns a value of a bit in the specified position.

`GETBIT(number, bit_position)`

Arguments:

• number - number to extract value of specific bit from

• bit_position - position of bit, starting with 0, from right

Examples:

• GETBIT(2, 0) → first bit of number 2 (0b0010) is 0

• GETBIT(4,2) → third bit of number 4 (0b0100) is 1

### GETBITS

Returns value of specified number of bits in the specified position.

`GETBITS(number, start_bit, number_of_bits)`

Examples:

• GETBITS(216, 3, 2) → number 216 = 0b1101 1000; value of 4th bit from the right is 1, 5th bit is 1, therefore result is 0b0011 = 3

• GETBITS(0xFF, 0, 4) → number 0xFF = 255 = 0b1111 1111; value of first 4 bits from right is 0b1111 = 0xF = 15

### GETBYTE

Returns a value of a byte in the specified number.

`GETBYTE(number, byte_position)`

Arguments:

• number - number to extract value of specific byte from

• byte_position - position of byte, starting from 0, from right

Examples:

• GETBYTE(256, 0) → 0001 0000 0000 → 0

• GETBYTE(256, 1) → 0001 0000 0000 → 1

• GETBYTE(259, 0) → 0001 0000 0011 → 3

### SETBYTE

Assigns a new value to the specified byte in the provided number and returns a new number.

`SETBYTE( number, byte_position, new_value)`

Examples:

• SETBYTE(1, 0, 0) → 0

• SETBYTE(256, 0, 255) → 511

• SETBYTE(256, 1, 1) → 256

• SETBYTE(259, 1, 2) → 515

### SETBIT

Assigns a new value to the specified bit in the provided number and returns a new number.

`SETBIT(number, bit_position, new_value)`

Arguments:

• number - number to be modified

• bit_position - position of bit, starting with 0, from right

• new_value - 0 or 1 - value that is going to be set to specified bit

Examples:

• SETBIT(1, 1, 1) → 3

• SETBIT(3, 1, 1) → 3

• SETBIT(4, 2, 0) → 4

• SETBIT(12, 1, 0) → 14

### SETBITS

Assigns a new value to the specified bits in the provided number and returns a new number.

`SETBITS(number, start_bit, number_of_bits, new_value)`

Examples:

• SETBITS(192, 4, 2, 3) → 240

• SETBITS(192, 5, 2, 3) → 224

### <<   (LEFT BIT SHIFT)

`8 << 2   (32)`

Excel: BITLSHIFT(number, shift_amount)

### >> (RIGHT BIT SHIFT)

`32 >> 2   (8)`

Excel: BITRSHIFT(number, shift_amount)

### & (BITWISE AND)

`3 & 1   (1)`

Excel: BITAND(number1, number2)

### | (BITWISE OR)

`2 | 1 (3)`

Excel: BITOR(number1, number2)

`0xA0A0   (41120)`
`0xa0a0   (41120)`