Description
The "Get maximum" instruction compares the values at the available inputs and writes the highest value to the OUT output. The number of inputs can be expanded at the instruction box by additional inputs. The inputs are numbered in ascending order in the box.
In its initial state the instruction contains at least two inputs (IN1 and IN2) and no more than 100 inputs.
The enable output ENO has the signal state "0" if one of the following conditions applies:
-
Enable input EN has the signal state "0".
-
The implicit conversion of the data types fails during execution of the instruction.
-
A floating-point number has an invalid value.
Parameters
The following table shows the parameters of the "Get maximum" instruction:
|
Parameters |
Declaration |
Data type |
Memory area |
Description |
|
|---|---|---|---|---|---|
|
S7-1200 |
S7-1500 |
||||
|
EN |
Input |
BOOL |
I, Q, M, D, L or constant |
I, Q, M, D, L, T, C or constant |
Enable input |
|
ENO |
Output |
BOOL |
I, Q, M, D, L |
I, Q, M, D, L |
Enable output |
|
IN1 |
Input |
Integers, floating-point numbers, DTL, DT |
I, Q, M, D, L, P or constant |
I, Q, M, D, L, P or constant |
First input value |
|
IN2 |
Input |
Integers, floating-point numbers, DTL, DT |
I, Q, M, D, L, P or constant |
I, Q, M, D, L, P or constant |
Second input value |
|
INn |
Input |
Integers, floating-point numbers, DTL, DT |
I, Q, M, D, L, P or constant |
I, Q, M, D, L, P or constant |
Additionally inserted inputs whose values are to be compared. |
|
OUT |
Output |
Integers, floating-point numbers, DTL, DT |
I, Q, M, D, L, P |
I, Q, M, D, L, P |
Result |
|
If the IEC check is not enabled, you can also use tags of the data type TIME, LTIME, TOD, LTOD, DATE and LDT by selecting a bit string of the same length as the data type. (e.g. instead of TIME => DINT, UDINT or DWORD = 32 bits) |
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You can select the data type of the instruction from the "???" drop-down list of the instruction box.
For additional information on valid data types, refer to "See also".
Example
The following example shows how the instruction works:
The following table shows how the instruction works using concrete operand values:
|
Parameters |
Operand |
Value |
|---|---|---|
|
IN1 |
TagIn_Value1 |
12222 |
|
IN2 |
TagIn_Value2 |
14444 |
|
IN3 |
TagIn_Value3 |
13333 |
|
OUT |
TagOut_Value |
14444 |
If the operands "TagIn_1" and "TagIn_2" have signal state "1", the instruction is executed. The instruction compares the values of the specified operands and copies the highest value ("TagIn_Value2") to output "TagOut_Value". If the instruction is executed without errors, the "TagOut" output is set.