using compactRIO for interlocking (in railway signalling)

[m_khani]

Interlocking as a major part of the Signaling system includes hardware and software components that must be safe. In this regard, some questions are raised about national instrument related products: CompactRIO and LabVIEW redundancy toolkit:

1. Could CompactRIO  be used in interlocking system as a main processor?
2. Has CompactRIO  any experience in railway applications (interlocking, on-board, CTC, CBTC, …)?
3. Is there a LabVIEW toolkit for creating 2oo3 redundancy configuration (redundancy for NI equipment such as CompactRIO or any typical computers).
4. Is there a test tool for formal verification of a LabVIEW program (for obtaining railway standards (EN50128))?

[AndyClegg]

You'd really need to have a system design that is based on a functional safety assessment, and I am sure a cRIO could be used within that for some functionality.

We were involved in a high safety critical system using a cRIO (marine, got certification), and the safety system design was done by somebody who was an expert in safety engineering. We just built the cRIO sw to do what that dictated. That system had an fully external safety system (hard wired safety relays), but that was interfaced to the cRIO so that it could also activate the safety system when it detected certain complex faults that the hard wired system could not (there were many fault conditions the sw could detect). The fault monitoring on the cRIO was coded in LV RT, but the signal passing to the DO to the safety system was handled by a small bit of code running on the FPGA - which also acted as a watchdog for the RT, so that if the cRIO RT application became unresponsive for any reason, the FPGA would also instigate a fault independent of the LV RT.

We didn't have redundancy on this system - that decision comes from the overall safety engineering assessment. There is no tools for redundancy in cRIO based systems, but it can be done - there was a white pape which I can't find, but if you search you will find people who have come up with solutions. However, do consider what you mean by redundancy - signal-level redundancy is relatively simple as is redundancy in comms, but controller hardware redundancy is normally what we think about (harder) and then there is functional redundancy in the software. Its a big subject

[santo_13]

I have come across this C-Series functional safety module in some other forum topics, may be useful to you since you talk about safety and redundancy.

https://www.ni.com/pdf/product-flyers/c-series-functional-safety-module.pdf

https://www.ni.com/en-us/shop/hardware/products/c-series-functional-safety-module.html

https://www.ni.com/en-us/shop/data-acquisition-and-control/what-are-c-series-functional-safety-modul...

[AndyClegg]

Santosh - I'd forgot about those yellow safety c-series modules. I don't think they were around when we built the system I was describing above. I'll have to have a refresh about them. Thanks

[m_khani]

thanks a lot