Using Traps

Traps enable a program to jump to a label or enable a function to be called when a certain event occurs.

Traps are divided into the following two types:

• 4 Traps are fired by user defined input
• 7 Traps are fired by system

You should keep trap functions short and avoid continuous loops. According to the type, some Traps must be re-armed. Also, some motion commands are limited to execute in trap functions.

For details on Trap commands, refer to the following manual:

"SPEL+ Language Reference"

Here is a simple example for a trap. In this example, when input 1 turns on, it executes the Sw1Trap function.

Function main
  ' Sets the trap
  Trap 1 Sw(1) = On Xqt Sw1Trap
  Do
    RunCycle
  Loop
Fend

Function Sw1Trap
  ' Turn on output 1 for 2 seconds
  On 1, 2
  ' Wait for trap condition to clear
  Wait Sw(1) = Off
  ' Re-arm the trap
  Trap 1 Sw(1) = On Xqt Sw1Trap
Fend

Trap	Description
Trap 1 - 4 Goto	Triggered by an input condition specified by the user. User traps can use GoTo, Call, or Xqt.
Trap 1 - 4 Call
Trap 1 - 4 Xqt
Trap Emergency Xqt	When Emergency Stop occurs, a specified function is executed.
Trap Error Xqt	When an error occurs, a specified function is executed.
Trap SgOpen Xqt	When the Safeguard circuit is open, a specified function is executed.
Trap SgClose Xqt	When the Safeguard circuit is closed, a specified function is executed.
Trap Pause Xqt	When the system enters the Pause state, a specified function is executed.
Trap Abort Xqt	When all tasks (except background tasks) have been stopped by user or system, such as when a command corresponding to Abort All is executed, a specified function is executed.
Trap Finish Xqt	When all tasks (except background tasks) have been finished, a specified function is executed. However, the function will not be executed under the condition that executes Trap Abort.