Watlow LogicPro - Manual (Page 66)

Chapter 6: Variables LogicPro User’s Guide
50 Watlow Anafaze Doc.# 28002-00 Rev 3.00
Retentive Variables
A Retentive Variable is a Variable that:
• Remembers its last state if power is interrupted.
• Returns that value after power has been restored.
LogicPro forgets all of the Variable values when a power
down of a Resource occurs unless they are tagged as
Retentive.
System Variables
System Variables give you access to internal system status
and allow you to view items such as I/O Driver and Resource
status. LogicPro generates these Variables automatically. You
can access System Variables through the
Variable List
dialog box in the same manner as Project, Resource, and
Program Variables.
Whenever an driver is referenced in your Program, LogicPro
creates two Variables, Flag and Stat, for each driver.
• Flag Variable — is Boolean in nature and goes high if
an error is detected.
• Stat Variable — is an integer and contains the river
status bits or error code.
LogicPro also creates system variables whenever function
blocks are added to a program. These variables can be used
elsewhere in the program. The system variables are named by
concatenating the user set name of the function block, and the
function block’s I/O symbols. For example, MYTIMER.Q is
a system variable that holds a value of 0 when the output of
function block named MYTIMER is off and a value of 1 when
the output of that function block is on.
To view the existing system variables or assign one to a
program element:
1. Double-click a program element.
2. For Variable Type, select System
3. For Data Type, select All
NOTE! You can view System Variables, only after having
defined a Variable associated with a particular
driver, and you cannot add, delete, or edit them.