watchdog timer documentation

[kgodett]

Hi,

I have a cFP-2120 that I am using to program in real-time mode.

Is there any documentation for how to use the watchdog timer? I've seen other threads where it looks like the timer won't start until after you whack it for the first time. Is this true, or will it start one I have configured it?

Also, is there a maximum length of time that can be used for the timeout?

Thanks

[Karunya_R]

Hi,

There are a set of shipping examples which demonstrate how to use watchdog timer. They are called watchdog occurence - RT engine.vi and watchdog reset - RT engine. You can also find other examples by just searching using the term watchdog. There is also an example online that demonstrates how to set up watchdog for the cFP 2020

If the purpose of using watchdog is protect your system from failure, consider using network watchdog. The best resource for this is the help file located at Start->Programs->National Instruments-> FieldPoint X.x -> FieldPoint Help. Then from the search tab use the keyword "watchdog".

Here are a few other resources for you:
Guarding Against Network Failures: How to Configure the Network WatchDog Timer for your FieldPoint?
FieldPoint WatchDog Timer
How Do I Use the Power Up and Watchdog Settings of the FieldPoint Modules Together?
FieldPoint Watchdog Timer Questions

The default timeout value is 1 second. If you want to disable expiration of the timer, set the value to -1. The primary purpose of the watchdog whack is to reset the counter. However, the whack can also be used to start the timer if its disabled or restart the timer after it has expired.

You can also use the LabVIEW help and search for watchdog.

I hope all this helps!

[kgodett]

Thanks for the help Karunya,

I was looking more for help with the hardware watchdog timer.

My ultimate goal for using the watchdog was for was for debugging purposes, because for some reason (still working on finding out why...) the controller completely stops responding. Rather than just hitting the reset button, I was using the watchdog timer to reset the controller. Because the controllers will be deployed about 2 hours away from where I work, I think it would probably be a good idea to keep them in the code.

I was trying to set the timeout values to a longer number, because I am communicating with a device over the serial connection, and parsing long stings which takes a while to get all the back and forth messaging done. I found that if I set the reset timer to 5 seconds it seemed to work, but longer values would not work. So was wondering if there is any actual documentation on the hardware watchdog timer aside from the VI include in the Real-Time programming examples.

The only information I could find in the help menu was about setting the network watchdog settings. I am mostly using my controllers to read data and pass it back to a server, so I don't have any outputs that I set back to a safe mode in the event of a network failure.

-Kyle

Message Edited by kgodett on 05-08-2008 03:36 PM

[Karunya_R]

Hi Kyle,

What happens when you set the timeout to more than 5 secs (screen shots would be great!)? When you say reset the control, do you  mean reboot the controller?

[kgodett]

Karunya,

I meant that I wanted to reboot the controller in the event of a watchdog timeout.

When I set the timeout value to more than 5 seconds, the program seems to behave as if the watchdog timer isn't there. I get a window that pops up saying that it is waiting for the real-time device to respond (the attached image cfp-freeze.jpg). If I have the watchdog timer running, this dialog will still pop up, but it will go away after a couple seconds (after the controller finishes rebooting).

If I do not include the watchdog timer, (or I set it to more than 5 seconds), I am unable to connect to the device until I cycle power, or press the reset button. When I open up the measurement and automation explorer, it will not see the device. (I do see the activity light on the field-point ethernet port blink though)

I am also attaching the top level module that I am using, in case that will be helpful. If you are willing to look through all my vi's to see what I might be doing wrong, let me know, and I can post the entire program.

Thanks again,

Kyle

[Karunya_R]

Kyle,

There is very little documentation on using Hardware watchdog and I apologize for that. Have you tried using this example?

There is also another examples under the real time for watchdog PXI.

There is also this discussion forum which has a fabulous watchdog example created by a customer. What fieldpoint driver version are you using?

I was unable to open up your VI because it was missing the following: DAQRead.VI, Fill_all_clusters.vi, Inverter read.vi, DAQ_Read_Cluster.ctl. If you do want me to test it out, It is probably better if you send me the entire code.

Thanks!