WAGO 750-841 interrupt system

Hi everybody!

I failed to find how it is possible to handle timer interrupt on 750-841. And how to set interrupt frequency?

I expect the same question about WAGO-I/O-IPC 758-870 would emerge as well.

Yes, I'm aware about SysInstallHandler function but have no idea about possible values of interrupt number parameter.

Thanks!

PS. Btw, CoDeSys is excellent software.

Steps:

1. Create a POU program that is what you want to execute on timed interrupt. In this example "MyTask"

2. Go to Resources tab in the tree view on the left of CoDeSys and open up the Task Configuration dialog.

3. Right mouse click on Task Configuration and select Append Task.

4. Name the task. In example "MyTaskTimer".

5. Configure the task to cyclic and set interval. T#10ms.

6. Right mouse click on new "MyTaskTimer" and select append program call and select "MyTask.

7. SHould be done.
















[Do not know what is up with the pictures.]

dash said:

Steps:

1. Create a POU program that is what you want to execute on timed interrupt. In this example "MyTask"

2. Go to Resources tab in the tree view on the left of CoDeSys and open up the Task Configuration dialog.

3. Right mouse click on Task Configuration and select Append Task.

4. Name the task. In example "MyTaskTimer".

5. Configure the task to cyclic and set interval. T#10ms.

6. Right mouse click on new "MyTaskTimer" and select append program call and select "MyTask.

7. SHould be done.

Click to expand...

Thank you Dash! Great!

However, it looks as it is impossible to install cyclic tasks with more than 1000Hz frequency.

I have a task to monitor time intervals between close discrete events in milliseconds with precision as high as possible.

Using Real Time Clock on 750-841 in microseconds (it consumes about 12musec I estimated time needed to perform operation (A:=B+1) as 1.2musec.

So short tasks could be performed 2, 3 or 4 times each millisecond. But...

Btw, what about 758-870? It is much more powerfull.

I think you are going to overload the processor/OS doing that. I doubt it can task switch that fast.

You could try this.

1. Go to "PLC Configuration" under the resources tab.

2. Assign a name to one of your discrete inputs, "MyInputTrigger".

3. Go back to the "MyTaskTimer" configuration and change it from cyclic to "triggered by event".

4. In the event field press the button with the elipsis "..." and choose your named input from the list under "System Variables" in the list on the left.

You may want to look into the update rates on the K-Bus. Also, note that the fastest (least amount of filtering) input module I am aware of is 0.2ms and I still think this would overload the processor if you are switching IO triggers at 1kHz.

Darren

{Edit}

You may also want to see if the K-Bus is updated sychronous or asynchronous with the other programs. I have never looked into this and you would most likely need to talk with one of the more senior Wago tech support people to get an answer on this.

You could also create a Global Variable called "gTrigger" as a BOOL data type. Then in you freewheel task have something like:

gTrigger:=Input02 OR Input03 OR Input04 OR Input05 OR Input06;

Then you could set your event to "gTrigger". From there you could roll your own sequence of events module if needed.

As far as the IPC you asked about, information about it is still difficult to get here in the US (if you can read German there is plenty of information) and I tend to stay away from things when they have not sold that many here in the US.

As far as marketing hype goes I can not wait to see how the 767 Speedway product turns out. If it has just 75% of the features and performance they claim, it will be a nice product. Unfortunately they have been talking about it for almost 2 years now.

Look here for info: http://www.wago.com/cps/rde/xchg/SID-53EFFEF9-1358C98E/wago/style.xsl/gle_680.htm

Darren

Thank you Darren!

Very interesting info indeed.

Btw, I tried (on 750-841) cyclic task with 1 msec interval. Really it repeats after 3-4 msec, not faster.

Warmest regards!

Sergey.

Hello SNP
Look into WAGOs new IPCs. The fastest is 758-876. There you can chose cyclic tasks with much higher freq. (You can chose mysec, not just millisec). BUT as previously posted, the K-bus is still the same and will be the limiting factor. You can overload these processors to, but it's not easy. With the old 758-870 the system could go down on overload. This will not happen with 750-874...876.

why you need it so fast, if needed speed do it the old analog way.
like using 555 for timers and have the inputs controlled by the plc.