I am working on a Honeywell gauge pressure transmitter. Transmitter is just reinstalled after repairing and range is 0-3460 mmH2O. Now at zero pressure it is showing -3.4 mmH2O. Tx doesn't have zero setting screw on it and I couldn't find zero setting in my hart communicator. Transmitter model is: STG73L and hart communicator model is MFC4100 Meriam.

Please help how can I set it to zero.

 

Honeywell's ST700 series is a smart transmitter, and like all smart transmitters does not have analog zero or span screws.

You face an incompatibility of the Meriam 4150 HART handheld and the Honeywell.

The Meriam 4150 uses model specific DOF files to communicate via HART to a smart transmitter. DOF files are not the same as DD files (which do the same thing, that is, provide communications for specific model/brands). Hence the 5150 will only do the universal commands - tag, units, LRV, URV, filter/damping

I know the 4150 had a DOF file that could talk HART to Honeywell's ST3000 pressure transmitters. But I doubt that the DOF file for an ST3000 will work with an ST700. You can try and see, but it's a long shot.

If I recall properly, the zero adjustment command for the ST3000 is 'zero trim' in the calibration group.

The DD/DTM zero adjustment command for the ST700 is "LRV correct", also in the calibration group.

The ST700's optional pushbuttons and local display have the 'LRV correct' command.

The Meriam 5150 replaces the 4150. The 5150 uses DD files and I'm sure that there is a DD for the ST700 series.

If you can get ahold of a USB HART modem, there is an ST700 DTM file for Windows Pactware configuration software. The Krohne and Vega versions are free downloads without licensing.

 

AhmadH,

If you did not buy the optional three button assembly to allow to externally zero the transmitter, you have to use a communicator to do the zero. I do not know anything about the MFC4100 Meriam communicator. You may have to read the communicator manual deeper or use a different communicator.

Regards,
Bill

William (Bill) L. Mostia, Jr. PE
ISA Fellow, SIS-TECH Fellow,
FS Eng. (TUV Rheinland)
SIS-TECH Solutions, LP

"No trees were killed tosend this message, but a large number of electrons were terriblyinconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

 

Because of the challenges with proprietary files many 4-20 mA devices these days come with the possibility to configure from the local display.

Zero trim is a common practice command so you should be able to do it in "generic HART access". This is support in the 475 communicator if you have one of those. "generic HART access" is extremely limited, but sometimes it is all you need - a real life saver.

Learn more about DD files and "generic HART access" from the device revision and life cycle management tutorial found here:

http://www.eddl.org/DeviceManagement/Pages/DeviceRevisionManagement.aspx

Cheers,
Jonas