Krohne Flowmeter Problem

Every modern magmeter has a low flow cutoff point, where flows below that value are reported in the display and on the output as zero flow.

The low flow cutoff value might be in percent of span or it might be in engineering units, you'll have to check and see.

So get the manual, find the low flow cutoff setting, check what units it uses and put in a number that will calm those concerned with flutters around zero.

1. Read the manual.

2. If you do not understand the manual, get someone who does.

If all else fails call Krohne and ask the tech line for troubleshooting help.

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Have you ever heard of a signal to noise ratio? When one has no signal then one only has noise. Thus a 0 db signal to noise ratio.

I also wonder about the idea that you have no flow when the pump is off. Are you really sure that a siphon or brief pressure wave might actually have some liquid sloshing about occasionally.

You could also just have an intermittent wire.

I think I've reached my WAG quota on this question.

You need to Zero the contoller when there is no flow, make sure there is solution in the pipe when you do this.If this fails you then can look at other issues.

you may want to try hooking a hart communicator since using the button converter is a hassle, make sure that the flow is zero on the line, look for auto zero button, it will automatically set your zero calibration, i had this problem before...if not, you may want to reset to factory settings and try setting again.

Make sure there is sufficient dissolved material in the liquid to enable the flowmeter to operate. Below about 50ppm TDS, magflow meters just don't work.

Does the pipe remain full when the pump is off? If the liquid level goes below the electrodes, the meter can generate random values.

One of the most common installation errors with magnetic flowmeters is improper (or absent) grounding. The EMF induced by a flowing liquid is very small (millivolts or less), and so the slightest electrical power leakage currents traveling through the liquid may be detected as (random) flows.

If you haven't already, check the manufacturer's documentation on proper grounding protocol, and follow those instructions to the letter.

In addition to the above, and if the facility exists, consider installing a control that says:

• If the output from the flowmeter is less than, say, 4.05mA, then call it 4.0mA.
• If the pump is not running, then irrespective of the output, call it 4.0mA.

and the problem may well go away.