User Manual
Chapter 11
GFK-1742F
Jan 2020
Local Logic Tutorial
276
11.2
Comments
Comments allow the programmer to describe program operation, or any information that
the programmer wishes to embed in the program. Comment text begins with the (*
character pair and terminates with the *) character pair and may appear anywhere within
the program. For example:
(* Valid Comment Structure *)
The DSM during program execution ignores comments. Thus, comment lines do not count
when determining local logic program length.
11.3
Variables
Local Logic provides the user access to motion controller data, control and status bits, and
parameters using a fixed set of variables. The language also supports decimal, hexadecimal,
and binary constants. Hexadecimal and binary value representations are unsigned
constants in program statements, but are ALWAYS interpreted as signed two’s
complement
in mathematical expressions. To assign a value to a variable the user would enter the
following
Torque_Limit_1 :=5000; (* Sets Torque Limit Axis 1 to 50% *)
or in hexadecimal form
Torque_Limit_1:=16#1388; (* Set Torque Limit Axis 1 to 50% *)
When variables are assigned a numeric value they are automatically limit checked to a
signed 32-bit value. For example the following values represent the largest positive and
negative values that are acceptable.
P001:=16#7FFFFFFF; (* P001=2147483647 *)
or in decimal form
P001:=2147483647; (* P001=16#7FFFFFFF *)
To assign the maximum negative value the user would enter
P002:=16#80000000; (* P002=-2147483648 *)
or in decimal form
P002:=-2147483648; (* P002=16#80000000 *)
If the user enters a number that exceeds the above numerical limits an error will be
generated indicating that the constant is out of range.
Local Logic
variables have a read, write, or read/write “directional” attribute. (Additional
information concerning the variables and their type are contained in chapter 13.) As an
example, the variable Positive End of Travel for Axis 1 (Positive_EOT_1) is a read only
variable. As such, the following is a valid construct:
P001:=Positive_EOT_1; (* P001 = Positive End of Travel Axis 1 *)
However, the following is an invalid construct: