CODESYS cyclic interrupt block equivalent

[Pandiani]

Hello to all,

I know there are a few people here very experienced with Codesys. I wonder does Codesys have something similar to OB35 in STEP7?

Cyclic interrupt blocks in STEP 7 are used when time specific calculations had to be performed, for example in case of using PID controllers. OB35 is by default 100 ms execution cycle (which can be changed in HWConfig), but there are other cyclic blocks of course. OB1 is not suitable for time sensitive calculations and updates.

Now, does Codesys have something similar and how in general PID controllers or any other similar time sensitive calculations are handled?

Thank you!

 

[Lare]

You can use cyclic or interval tasks and set cycle time to 100ms.

 

[ndzied1]

As Lare mentioned, you can run a program on a task that has a defined cycle time. You can also give priorities to tasks so something like a fast PID would be run on a task with a high priority.

But, many hardware suppliers that support CoDeSys have their own libraries that support PID (and other) types of controllers. They may have instructions to use them in a task with a specific cycle or they may take a cycle time parameter and look at the free running clock in the hardware and deal with it that way. Of course, the task should update at least as frequently as you want the controller to update.

There is also an open source library called Oscat (http://www.oscat.de/de/). This library includes several controllers. You can download the source files to see how they achieve different controls.

I haven't done any fast controllers so I haven't worried much about this but I have looked at it and there seem to be a lot of options to do things.

 

[Pandiani]

Thank you very much for the replies.
I'll investigate options. Oscat looks very interesting.