Process Type Instructions
Process type motion instructions initiate motion processes that can take an indefinite amount of time to complete.
Examples of process type instructions include the:
- Motion Arm Watch Position (MAW) instruction
- Motion Axis Move (MAM) instruction
Process type instructions work as follows:
- When the rung that contains the motion instruction becomes true, the controller:
- Sets the enable (.EN) bit.
- Clears the done (.DN) bit.
- Clears the error (.ER) bit.
- Clears the process complete (.PC) bit.
- The controller initiates the motion process.If:Then the controller:The controller does not detect an error when the instruction executes
- Sets the .DN bit.
- Sets the in process (.IP) bit.
The controller detects an error when the instruction executes- Sets the .ER bit.
- Stores an error code in the control structure.
- Does not change the .IP and .PC bits.
The controller detects another instance of the motion instructionClears the .IP bit for that instance.The motion process reaches the point where the instruction can be executed againSets the .DN bit.Tip:For some process type instructions, like MAM, this will occur on the first scan. For others, like MAH, the .DN bit will not be set until the entire homing process is complete.One of the following occurs during the motion process:- The motion process completes
- Another instance of the instruction executes
- Another instruction stops the motion process
- A motion fault stops the motion process
- Sets the .DN bit.
- Sets the .PC bit.
- Clears the .IP bit.
- Once the initiation of the motion process completes, the program scan can continue.NOTE:The remainder of the instruction and the control process continue in parallel with the program scan.
- The next time the rung becomes false after either the .DN bit or the .ER bit sets, the controller clears the .EN bit.
- When the rung becomes true, the instruction can execute again.
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