|
SUB |
  
|
|
SUB |
|
Block that calculates the subtraction between the Value1 and Value2 values, storing the result in Result.
Ladder Representation
Block Structure
Variable Type |
Name |
Data Type |
Description |
VAR_INPUT |
EN |
BOOL |
Block enabling |
Value1 |
BYTE USINT SINT WORD UINT INT DWORD UDINT DINT REAL |
Minuend of operation |
|
Value2 |
BYTE USINT SINT WORD UINT INT DWORD UDINT DINT REAL |
Subtrahend of operation |
|
VAR_OUTPUT |
Done |
BOOL |
End of operation |
Result |
BYTE USINT SINT WORD UINT INT DWORD UDINT DINT REAL |
Variable that stores the result of the operation |
Operation
When this block has a TRUE value in EN, it sends to the Result output the subtraction of Value1 and Value2 variables. If no errors, the Done variable is set. If there is any error in the operation, Done is not set, staying in FALSE status, while Result remains with its value unchanged.
When EN has FALSE value, Result remains unchanged and Done remains in FALSE.
Block Flowchart
Example in Ladder
The above example calculates the subtraction of VALUE 1 and VALUE2 variables, storing the final result in RESULT.
The above example calculates the subtraction of VALUE 1 and VALUE2 variables, storing the final result in RESULT. Notice that the block accepts arguments of both signs.
The above example calculates the subtraction of VALUE1 and VALUE2 variables. The final result 141 cannot be stored in RESULT, because it is outside the limits of accepted values by SINT type. Therefore, RESULT remains unchanged and the output is disabled.
Example in ST
The example below displays the instructions for applying the example above in the ST language.
VAR VALUE1 : SINT := 52; VALUE2 : SINT := -17; RESULT : SINT; END_VAR
RESULT := FB_SUB( EN:=DI1, Value1:=VALUE1, Value2:=VALUE2, Done=>DO1);
|
|---|