User Manual
Chapter 11
GFK-1742F
Jan 2020
Local Logic Tutorial
277
Positive_EOT_1:=1;
The Local Logic Parser generates an error if the program attempts to write to a read only
variable, or attempts to read a write only variable.
In addition, Local Logic variables have a size attribute ranging from Boolean (1-bit) to double
integer (64-bits). The Local Logic Parser generates a warning message when a non-Boolean
value is assigned to a Boolean variable. The warning indicates that data may be lost, due to
truncation, when this assignment occurs. The user should note that double integer variables
(64-bit) variables may only be used as the destination of a multiply operation, or the
numerator of a divide or modulus operation.
Consult chapter 13 for additional information concerning Local Logic variables. Additionally,
the Local Logic Variables Table (LLVT) within the programming software contains the
information on the variables size, type and Read/Write properties.
11.4
Operators
Local logic provides three classes of operators. The operators are arithmetic, relational, and
bitwise logical operators. An introduction to each operator follows. A more detailed
discussion of the operators is contained in Chapter 12.
11.4.1
Arithmetic Operators
Local Logic provides the user with the ability to perform basic arithmetic operations. The
language supports 32-bit integer operations and limited use of 64/32 bit operations where
appropriate to maintain precision. All arithmetic functions, except the ABS function, require
two operands.
Local Logic supports addition, subtraction, multiplication, division, absolute value, and
modulus operations.
Example constructs are:
P010 := Commanded_Velocity_1 - P009; (* P010=Commanded Velocity Axis 1
–
P009*)
The user should note that the following would be an invalid mathematical construct:
Commanded_Velocity_1 := P010 - P009; (* Commanded_Velocity_1=P010-P009*)
The reason this is invalid is that the mathematical expression is attempting to assign the
result (P010-P009) to Commanded_Velocity_1 which is a read-only variable.
Storing intermediate results into parameter registers provides the flexibility necessary to
solve complex mathematical expressions.
For example, the following construct is invalid since it contains more than one operation
(Multiply and Subtraction):
P005: = Torque_Limit_1 *( P001
–
P010);
To achieve the same result, the user can enter the following:
P004: = P001
–
P010;