cRIO Profibus - different behavior with controller power cycle vs controller reset

[Chris_12345]

We have a cRIO-9025 controller with a 9118 backplane and a Profibus module, running with LV2014. The Profibus module is connected to equipment, and communications works fine. However, if power to the cRIO/Profibus is turned off and on again, we lose the Profibus communications to the equipment. Pressing the reset button on the cIO controller restores communication. This is repeatable behavior.

We have tried powering up the controller followed by powering up the Profibus module, and vice versa, but the behavior is the same: cycling power to the cRIO controller causes Profibus communication failure, but pressing the cRIO reset button restores it. My uinderstanding is that the cRIO reset button is functionally equivalent to a power cycle, yet we are seeing different behavior for the Profibus communications.

Any ideas on what might be causing this difference in behavior?

[Miro_T]

Chris,

Can you give me more detailes about your system setup? Is the controller running real-time exe? Do you have some kind of watchdog setup between RT and FPGA?

What is your chassis reset options setup? See page 13 of the 9118 manual http://www.ni.com/pdf/manuals/375079d.pdf#page=13

Is the Profibus module master or a slave in your network?

Thanks

[Chris_12345]

Miro,

Thank you for the quick response. The controller is running a Real-TIme exe, which performs a variety of functions, such as reading in data from DAQ modules, publishing the data out the Ethernet socket, and communicating with the Profibus module.

After cycling the power, the Real-Time exe performs all its functions properly, except for the Profibus communications. So, I am confident that the problem does not originate with the RT - FPGA link. Subsequently pressing the reset button corrects the Profibus communications. Cycling the power again reproduces the Profibus comunication problem.

The reset options are configured such that cycling the power or pressing the reset button causes the Real-Time exe to start running automatically.

The profibus module is the master.

-Chris