Mathematics

The mathematics job is not only offering all usual mathematical operations but beyond that also a lot of mathematical functions. At the end of this description, you will find some examples for this.

EIS Formats

The math job supports the following datatypes at the input- and output-object.

• EIS 1 (1 Bit)

• EIS 5 (2 Byte FP)

• EIS 6 (1 Byte)

• EIS 9 (4 Byte FP)

• EIS 10s (2 Byte Value)

• EIS 11s (4 Byte Value)

• EIS 14u (1 Byte unsigned)

• EIS 15 (14Byte Text)

Beside that the jobs disposes a gate object as well as an EIS 14 output for an error code and an EIS 15 text output for an error text. They are given out when the flag “Runtime Errors” is activated.

Job Name

Required field. Assign a unique name for the job. The name must not contain more than 15 characters.

Gate Group Addresses

By Gate Group Addresses job will be released or blocked. It is about an EIS1 object:

• Field blank = Job is released.

• Field completed, value 1 = Job released.

• Field completed, value 0 = job locked.

• Field completed, no value = job locked.

As soon as one address is filled in, release will behave respective to the value of the group address. If no value was sent to the address and the address is presently without values, job will be blocked.

Runtime error issue

If this flag is enabled, error codes and error messages via EIS 14 EIS issued by telegram 15. The addresses to be entered into the fields below. An overview of error codes is at the end of the job description.

Exit / access to the initial value

The value of the output object can use the variables "eo_out ()" is also used for the calculation. The operation can never be "eo_out ()" is triggered.

Inputs

Each mathematics job contains 12 input objects. This could correspond to the above-mentioned datatypes. Also, can be determined when a telegram abutting the selected input to calculate the formula. To enter a group address either the keyboard or the ESF-Dialogue can be used. For the ESF Dialogue the arrow button next to the address entry array has been pressed. You will reach the overview of the data which will be uploaded into the EIBPORT before (also see chapter “KNXnet/IP | ETS”).

Note: All values within the mathematics job are generally calculated unsigned, i.e. without signs. If you want values to be shown with signs, please make the appropriate settings in the visualisation element.

Calculation of the formula

The selection in the dropdown menu determines when the calculation of the formula is triggered in the mathematical expression:

• Always: The calculation will be triggered when any input is detected at the input object.

• Never: The calculation is that input never initiated. Of course, the value of the input object in the execution of the operation is considered.

• If the value is changed: Only if changing the input value against the previous value, initiated a calculation.

Access onto the input in the mathematical expression

To use the input objects for the mathematical expression the following syntax applies:

• The inputs 1-12 own the index numbers 0-11.

• By entering “eo(number of index)” the respective value of the input objects has been fetched for the mathematical expression. For the input 1 so is entered “eo(0)”.

• If the other way round the index number of an object should be issued (and eventually continue to use) on which at last a telegram was incoming, it can be done by entering “eoi()”.

Mathematically Expression

In this array the required mathematically expression will be put together. Doing this the usual mathematical rules applies. To output the result, it is too considered that the value of the result is not exceeding the range of the datatype set in the output object. The following operations are available:

Note: Internally, the math module can work with floating point numbers or texts.

Mathematical operations

Logical (boolean) operations

Other operations

Built in Functions

Datatypes and Strings:

Note: A "." (period) must be used as decimal separator, otherwise the expression becomes invalid.

Predefined constants:

Self-defined variables and multiple expressions after another:

“a=10” allocates the variable “a” the value 10. “a=1; b=2; a+b” allocates the values 1 resp. 2 to the variables “a” and “b” and is giving out the result “3”.

Important: That way defined variables only have a limited validity within one calculation of one expression!

Reservierte Variablen

Examples:

Here some examples so that the using of the several functions and operations becomes a little bit clearer:

• „eo(1) + 100“ -> Is giving out the EIB-object with the number one (hereafter EO_1) added by 100. Of course, every time important is paying attention to the possible range of the EIB output object!

• „eo(3)*eo(4)“ -> Multiplies EO_3 and EO_4. If there are EIB-objects which are not provided with a groupaddress, a failure is beeing noticed.

• „100 / eo(1)“ -> Divides 100 by EO_1. Attention: If a null is being sent on the input 1 the calculation is giving out a runtime error! (“Division by null”).

• „sqrt(eo(0)^2+eo(1)^2)“ -> Is calculating the length of the hypothenuse in a right angled triangle, if on EO_0 und EO_1 the length of the catheters is beings sent („Pythagorean theorem“).

• „eoi()“ -> Is giving out a 2 if something is received on the EIB-object with the number two.

• „eo(eoi())“ -> Is giving back the receiving value.

• „eo(eoi())^2“ -> Is calculating the square for every transceiver telegram value.

• „rand()“ -> Is giving out the random value.

• „rand() & 0xff“ -> Limits this value on a range from 0 to maximum 255. So, the result must be presentable in EIS 14.

• „srand(time())“ -> Ist giving out nothing (resp. null), but is initializing the random generator with a pseudo-random start value.

• „eo(0)+eo(2)+eo(3)+eo(1)+eo(5)+eo(6)+eo(4)“ -> Is calculating the sum of multiple EIB-objects.

• „eo_sum(0,1,2,3,4,5,6)“ ->Like above, but plenty more „runtime-friendlier“ and more insight.

• „"foo" + "bar"“ -> Is giving out the result „foo bar“. This only works if the output is switched to EIS 15 datatype.

Error Codes and Error text