User`s manual

iNspect Express User’s Manual405-00026-00
87Rev 1600; 12 July 2010
Equations allow you to communicate with PLC devices. You define a PLC device, then assign
variables names to the register locations. You use Equations to read and write to the variable
names and manipulate values. Variables created here can be used for Conditional Outputs.
The Equations or Assignment Equations are grouped under Functions. The Function determines
when the equations are executed. Only the first 3 functions are displayed in the drop list by de-
fault. Use the New button to add the other pre-defined functions.
• Pre Image Process – called after the image is acquired, before the image is processed.
• Post Image Process – called after each acquired image is processed.
• Solution Initialize – called once when a new solution is loaded.
• Periodic – called periodically with the specified interval between calls.
• User – a user function can be called from the other function types or other statements. You can
define the number of parameters passed: 1, 2 or none. You cannot rename the parameters. Ev-
ery User function must include the return function.
• Delayed Event – called at a defined time after (a) image acquired or (b) end of processing.
• PLC Variable Change of State – called when a PLC variable or register changes value or state.
This applies only to Ethernet/IP and Modbus Slave PLCs (not a Modbus Master).
• Input State Change – called when a specified input (GPIx) changes state.
The Configuration and Status window shows the equations contained in the selected Function.
appear in this field.
Select a statement
Equations are executed in the order they
then use the arrow
buttons to change
the order of statements
Manage Equation Execution Order
There are many pre-defined variables with special meaning for your use. You can also create your
own variables. Referencing a variable automatically creates or instantiates that variable. A sepa-
rate step for creating or declaring, is not necessary.
Statements are formed in a plain algebraic format, for example: a = b+c