Vibration value discrepancy between ADRE and HMI

Hi All,

I appreciate your thoughts about this case.

Turbine Casing vibration is measured by accelerators and it is connected to BN 3500 rack.The HMI reading for this probe is 25 mm/s PK while when the ADRE is connected to the rack the reading was 10 mm/s PK.

I am pretty sure that the ADRE values are correct , but the question what could make the reading at the HMI is higher than the double ?!!

what are the signal pressessing between the 3500 rack and the HMI that can cause that ?

what are the configuration at HMI that could be checked ?


You should provide :

Unit frame /process utility
Controls systems installed ..

A app code or at least signals exchange list /device summary is necessary to tell you with signals are processed through ADRE and BN3500 rack.

If both sets of field-wiring are in the same terminal-wiring panel, then switch the wiring positions ! What happens to the readings?
Regards, Phil Corso
Depending on the age and packager of the turbine and control system many of the B-N (Bently-Nevada) measurements were "transmitted" to the HMI using different methods, and in some cases the raw values (usually 4-20 mA and in some cases the actual proximitor voltage) was scaled using CIMPLICITY CIMEDIT methods. A lot of the early implementations of this were less than optimal and were not caught and corrected during commissioning. Later units transmitted scaled signals from the Mark* to the HMI using EGD (Ethernet Global Database) (so, via the UDH (Unit Data Highway) and would not have required any scaling in the HMI, but some of the early implementations of this method of transmitting signal values weren't really ready for prime time, either, and weren't always caught and corrected during commissioning either. (CIMPLICITY display issues requiring LOTS of attention far outnumbered basic machine control and protection issues--FAR outnumbered them in most cases! Some commissioning personnel attempted to fix these issues themselves and only succeeded in make the problems worse in some cases, and others recognized they required factory assistance to correct the issues (though some were too egotistically challenged to ask for the help and assistance preferring to bull their way through the problems over days and weeks and months in some cases.)

Without a LOT more information, it's really difficult to say what could be causing the discrepancy. Someone needs to review the configuration at the site and make some determinations about where the problem could be and proceed from there. The information required is probably too detailed to obtain via this public forum (unless the site were willing to share the application code and CIMPLICITY displays/project--which most sites aren't willing to do these days (privacy concerns being what they are in these times). So, best to get someone who's knowledgeable to site (and while there are GE field service personnel who might be knowledgeable in the various methods used over the past couple of decades, they are few and far between and most will just come to site and send files to off-site personnel to review and correct--all at great expense and a long time to fully resolve).

Best of luck!