### 1.2 The function block description format

The description of each function block consists of several sections (in the following order):

Block Symbol – displays the graphical symbol of the block
Function Description – brief description of the block function, omitting too detailed information.
Inputs – detailed description of all inputs of the block
Outputs – detailed description of all outputs of the block
Parameters – detailed description of all parameters of the block
Examples – a simple example of the use of the block in the context of other blocks and optional graph with input and output signals for better understanding of the block function.

If the block function is obvious, the section Examples is omitted. In case of block with no input or no output the corresponding section is omitted as well.

The inputs, outputs and parameters description has a tabular form:

 $\left[nam\right]$ Detailed description of the input (output, parameter) . Mathematical symbol $nam$ on the right side of the first column is used in the equations in the Function Description section. It is listed only if it differs from the name more than typographically. If the variable value is limited to only enumerated values, the meaning of these values is explained in this column.  [$\odot$] [$↓$] [$↑$]

The meaning of the three columns is quite obvious. The third column contains the item <type>. The REXYGEN control system supports the types listed in table 1.1. But the most frequently used types are Bool for Boolean variables, Long (I32) for integer variables and Double (F64) for real variables (in floating point arithmetics).

Each described variable (input, output or parameter) has a default value <def> in the REXYGEN system, which is preceded by the $\odot$ symbol. Also it has upper and lower limits, preceded by the symbols $↓$ and $↑$ respectively. All these three values are optional (marked by [ ]). If the value $\odot$<def> is not listed in the second column, it is equal to zero. If the values of $↓$<min> and/or $↑$<max> are missing, the limits are given by the the minimum and/or maximum of the corresponding type, see table 1.1 (Precise range of the Large data type is -9223372036854775808 to 9223372036854775807.).

 Type Meaning Minimum Maximum Bool Boolean value 0 or 1 0 1 Byte (U8) 8-bit integer number without the sign 0 255 Short (I16) 16-bit integer number with the sign -32768 32767 Long (I32) 32-bit integer number with the sign -2147483648 2147483647 Large (I64) 64-bit integer number with the sign $-9.2234\cdot 1{0}^{18}$ $9.2234\cdot 1{0}^{18}$ Word (U16) 16-bit integer number without the sign 0 65535 DWord (U32) 32-bit integer number without the sign 0 4294967295 Float (F32) 32-bit real number in floating point arithmetics $-3.4\cdot 1{0}^{38}$ $3.4\cdot 1{0}^{38}$ Double (F64) 64-bit real number in floating point arithmetics $-1.7\cdot 1{0}^{308}$ $1.7\cdot 1{0}^{308}$ String character string

Table 1.1: Types of variables in the REXYGEN system.

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