We have a reliability problem in the plant, particularly with Vibration Transducer Interface MTL4031.

Within a period of one year (since Oct 2009), we have to replace 18 units of it! It has caused unplanned plant shutdown twice.

It is connected to Bentley Nevada vibration probes and Bently Nevada 3500 Series Monitor. From the Data Manager 2000 system, the first symptom was erratic/spiking reading. Upon checking, we noticed it indicating Gap Voltage around -6V instead of the normal -9V. Immediately replacing the MTL4031 unit with a new one seems to solved the problem, i.e. Gap Voltage back to normal -9V and no more erratic/spiking reading. The one causing plant shutdown was when we let the spiking get too much and hit the HH level.

What puzzled us is it kept failing one after another, with similar symptom.

Has anybody experience the same thing? Could anybody suggest how should we troubleshoot the problem to find the root cause?

We installed the MTL4031 for various compressors/machine's vibration monitoring in a dedicated cabinet, back in 2001. Some quarter suggest the problem has something to do with grounding system but we are unsure as to how to confirm this.

Appreciate kind response.

Best regards,
M Mastan

 

Hi M Matan,

why you don't use galvanic isolators for the 3500 Series Monitor, 1701 Fieldmonitor or Trendmaster DSM?

I think it is not related to grounding system as galvanic isolators are used in areas where a high quality ground is not available.

Regards.

 

Hi all,

Just to share the troubleshooting outcome of the problem.

We did sent the faulty MTL4031 to MTL. Later MTL confirmed that there is problem with those unit, and recommending we replace all of them. As per the MTBF calculation, after nearly 10 years of operation, we could expect the barrier to be not 100% reliable anymore.

We have the test report for those interested although MTL may not allow it to be shared with others. But hey what the heck. At least those who use the same model could start planning to replace, etc.

 

we currently have the MTL4031 & MTL4073 and i could do with some guidance as my background is Electrical not Instruments.

The MTL4031 that we have in place at the moment has the Certificate Number BASEx94C2265 (PRE ATEX) the only Relevant Certificate that i can find that relates to the MTL4031 is BAS01ATEX7167. Where it confuses me is it mentions Galvanic Isolations Between SAFE & HAZARDOUS areas and it also mentions ZENER / DIODES.

Can you guys tell me if the MTL4031 & MTL4073 are Galvanic or Zener Barriers?

 

MTL announcement a replacement model in the middle of 2010. Contact MTL!

Phil Corso

 

We have a barrier that is also for vibration, is the D1062S, if anyone would like to test it I will send a sample.

http://www.gmisafety.com/?pid=D1062S

www.gmisafety.com