Fieldbus I/O checking

[dearkd]

Hi all,


I want to know the best way to do the Factory test for the
Fieldbus I/O.

The way we are adapting is first checking the segment wiring by directly
connecting a instrument in place of trunk cable.

Then starting checking each I/O with range,alarm and graphic displays.

Is there any better way ?

[spragujl]

We've had lengthy discussions in our company on the best way to do FF FAT testing. We are not yet satisfied that we have the tools to get the complete FAT that we need. There seems to be 2 parts to the FF FAT:

1) The FF H1 physical hardware/communications checks
2) The FF logic tests including display graphics

Everyone seems to agree the physical hardware/comms tests are needed - like your connecting one transmitter to each segment to verify communication, bulk power supply and Fieldbus power conditioner.

But there are different opinions on the logic tests. Most agree it's impractical on a large job to bring in all FF devices for FAT. Some opt to one-time test each standard loop/monitoring configuration on a single segment, others simulate FFIO using external or internal software simulators, others do no logic tests.

Up to now, we are doing the physical/communication test on each segment, along with a one-time, one-segment FAT logic test using each type of FF instrument + each type of basic loop/monitoring configuration.

However, it seems to me that host DCS vendors need to provide users with a better method to FAT verify our software configuration. A good way would be a simulator tool that is capable of taking a download of my conventional + FF DCS configuration, and then providing a high-resolution simulation of all I/O to my DCS controller. It would need to give me I/O simulation for all types of FF instrument, including those of different vendors and DD rev numbers.

Any DCS vendors our there working on such a simulator?

[dearkd]

hi

Thanks for the reply.

I agree with you for the method of the FAT.

However, the only reason is when we connect this type of simulator or some mimic processors, we cannot get some alarms like over range etc.

How to check this alarms ?

Is any of vendors like to clarify this thing ???????

[chriss]

Hi,

the described method to check the physical layer is good if you want to check if the things work. However you don't really know the real situation of the physical layer- as the fieldbus is relatively robust (we had some installations where they had a too high noise level and it was still working) you may have a problem but you don't realize it yet.

To get an accurate report of the physical layer you can use the advanced diagonsitc module (see http://www.pepperl-fuchs.com/pa/news/08827/index2_e.html) which is also available in a mobile version. With this tool you can get reports about the real status of the physical layer, e.g. a polarity check of your field devices; the noise and jitter values etc.