This query mainly concerns accessing Advanced Diagnostics information on SIS loops.
I have been speaking with a few customers on utilizing Advanced Diagnostics such as SPM & Loop Integrity Detection on 3051S transmitters in SIS loops. The biggest challenge is accessing the information since most SIS loops run purely on 4-20mA and do not have HART capability. One of the ways to attach THUMS to the transmitters and take diagnostics information out through WirelessHART.
But sometimes, the customers may not yet be willing to adopt Wireless or do not have AMS in their plant. In such a scenario, how useful is it to simply drive saturation alarms as a means to communicate diagnostics information? The operator can then find the specifics of the diagnostics alarm on the transmitter LCD screen or through their 475 handheld.
Will this method be useful in a 2 out of 3 voting scenario? Can we also use it in a 1 out of 2 voting scenario or will it trigger a plant trip?
Well, it's been a year since this thread got started and no one replied. I just joined today so I'll see if I can shed some light on the situation. Personally, I would not use saturation alarms to implement what you suggest for the following reasons:
1. Diagnosing a trip based on a saturation alarm that may/may not come from a SPM failure would be very difficult to do. A root cause analysis will be done on why the trip happened, and everyone will just end up blaming the SIS for a spurious trip when there would be a real problem in the field instead.
2. This will likely cause more spurious trips of the SIS unless you put in deadband limits on the alarm and really think through the programming. I don't think you can do that in the transmitter.
Ultimately, the client needs AMS to view the diagnostics. The alerts should be alarmed in the AMS with maintenance going out to check the transmitters. Tripping a plant based on this will probably cause the plant to operate on bypass, which is not what we want.
Alan Harris | Solution Consultant | Process Systems & SolutionsM (512) 239-9273Alan.Harris@Emerson.com
In reply to Alan Harris:
Thanks for chiming in, Alan. Abhishek did this help solve your problem? We will work to ensure we have SIS folks keeping a close eye on this group as it continues to grow so you can expect a more prompt response.
Best~
Rachelle McWright
365 Community Manager
Best Regards,
Rachelle McWright: Business Development Manager, Dynamic Simulation: U.S. Gulf Coast