Endress+Hauser Promag and Promass Flow Meters, New Zealand

Endress+Hauser / Promag and Promass flow meters

A flow meter is a calibrated pair. The sensor carries a calibration factor unique to that individual sensor, and the transmitter has to be told what it is. Fit a transmitter without entering the sensor's calibration data and the meter will read confidently and be wrong.

That is the single most expensive mistake on this product line, because nothing looks broken afterwards.

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The sensor and the transmitter are a matched pair

Part	What it holds
The sensor	A calibration factor from its individual factory calibration
The transmitter	The electronics, which must be given that factor

The calibration value is printed on the sensor nameplate. It is specific to that physical sensor, because each one is calibrated individually on a flow rig.

Situation	Outcome
Transmitter replaced, calibration data entered	Correct readings
Transmitter replaced, data not entered	Plausible readings, systematically wrong
Sensor replaced, transmitter not updated	Same problem in reverse

There is no alarm for this. The meter reads, the trend looks normal, and the number is out by a percentage nobody notices until a mass balance or a reconciliation fails.

So photograph the sensor nameplate before you touch anything, and keep it with the job. On a plant where flow determines yield, product accounting or trade, that photograph is worth a great deal.

If the two were supplied as a set, tell us, because we quote them as a set.

Promag against Promass

	Promag	Promass
Principle	Electromagnetic	Coriolis
Measures	Volumetric flow	Mass flow, and density
Requires	An electrically conductive liquid	Almost any fluid
Pressure drop	Effectively none. Full bore	Some, depending on size
Typical use here	Water, wastewater, milk, slurries	Product transfer, dosing, high value liquids
Cost	Lower	Higher

A Promag cannot measure a non-conductive fluid. Oils, most solvents and demineralised water below the minimum conductivity will not work, and that is physics rather than a fault.

A Promass measures mass directly, which is why it turns up where the measurement is the product, not just an indication.

Earthing is the number one Promag problem

The most useful troubleshooting content on this page, because the symptom looks like a failed meter.

A magnetic flow meter measures a very small voltage generated in the liquid. For that to be readable, the liquid and the meter have to share a stable reference.

Symptom	Very often
Reading noisy or jumping around	Earthing
Reading drifts with plant activity	Stray currents, or a drive nearby
Worse when a nearby motor runs	Earthing and screening
Reads high or low consistently	Calibration data, or installation

What actually needs checking

On plastic or lined pipework the liquid has no earth reference unless something provides one. That is what earthing rings, earthing electrodes or an earthing bridge are for.

Check	Why
Earthing rings fitted on lined or plastic pipe	Without them the measurement floats
Earth straps across the flanges	Continuity around the meter
A single clean earth point	Multiple earths create loops and stray currents
Signal cable screen terminated correctly	One end, per the installation instructions
Distance from drives and their motor cables	A drive motor cable is a strong noise source

A noisy magmeter next to a variable speed drive is one of the most common instrument complaints in a New Zealand plant room, and replacing the meter does not fix it.

Installation decides whether the reading is trustworthy

Worth checking before condemning any flow meter.

Requirement	Why
The pipe must be full	A partly full pipe reads nonsense. The most common cause of strange numbers
Straight lengths upstream and downstream	Bends, valves and pumps disturb the profile
Position in the pipework	Rising pipe or a low point keeps it full. A high point traps air
Electrode orientation on a magmeter	Electrodes on the horizontal axis, so air does not sit on them
Flow direction	Marked on the meter
Support and vibration on a Coriolis	It measures a vibrating tube. External vibration interferes

Empty pipe detection exists because partly full pipes are so common. If a meter reports empty pipe or reads erratically at low flow, the answer is usually the pipework, not the meter.

And a Coriolis meter is a vibrating tube. Mounting it rigidly to a structure that carries pump vibration, or to a pipe that is not properly supported, degrades the measurement. Two Coriolis meters on the same line can interfere with each other for the same reason.

Zeroing a Coriolis meter

Specific, frequently done wrong, and free to get right.

A Promass is zeroed under process conditions, with the pipe completely full and absolutely no flow.

Condition	Why
Pipe full of the actual process fluid	Not water, not air
Zero flow, valves closed	A leaking valve ruins the zero
At operating temperature and pressure	Both affect the tube
Plant quiet	Vibration during zeroing is captured into the zero

A leaking isolation valve during zeroing is the classic error. The meter learns a small flow as its zero, and every subsequent reading is offset by it. Then the meter gets blamed.

A meter that reads a small flow when the line is shut is telling you either the zero is wrong or a valve is passing. Both are worth knowing and neither is a new meter.

Liner and electrode materials on a Promag

Aspect	Matters because
Liner material	Must suit the product, the temperature and the CIP chemicals
Electrode material	Corrosion and coating resistance
Abrasion	Slurries wear liners out
Temperature cycling	CIP cycles are harder on a liner than the product is

A coated electrode reads badly before it reads not at all. On a product that deposits, gradual drift and increasing noise over months is often coating rather than electronics.

So on a dairy or process line: tell us the product and the CIP regime, not just the pipe size. The liner is what decides how long the meter lasts.

What you can replace on its own

Failed	Order
Display blank, output fine	Display module
Electronics failed, sensor sound	Transmitter or electronics module, plus the sensor calibration data
Liner or electrodes damaged	The sensor
Housing or cover damaged	Housing parts
Remote cable damaged	The cable. It is a specified part, not generic

Remote mount versions use a specific signal cable between sensor and transmitter, with a defined maximum length. Substituting ordinary cable produces exactly the noisy, drifting readings people blame on the meter.

Before ordering a replacement

Symptom	Check first
Noisy or jumping reading	Earthing, screening, and proximity to drive cables
Nonsense at low flow	Whether the pipe is actually full
Reads flow when the line is shut	Zero point, or a passing valve
Consistently out by a percentage	Sensor calibration data in the transmitter
Gradual drift over months	Electrode coating, or liner wear
Coriolis unstable	Vibration, pipe support, or another Coriolis nearby
Reading zero, no output	Loop power and wiring before the meter
Fails after a transmitter swap	The calibration data was not entered

What to send us

Photos of both nameplates. Sensor and transmitter, because they are separate items with separate order codes.

The sensor calibration value, which is on the sensor nameplate.

The line size and process connection.

The product, the temperature and the CIP regime.

The output signal, and what reads it.

Whether it is compact or remote mount.

Whether it is in a hazardous area.

What failed, because the display or electronics module may be the answer.

What we can supply

Meters. Promag and Promass across the current generations, plus Prowirl, Prosonic Flow and t-mass, configured to your order code.

Obsolete generations. Earlier Promag and Promass transmitters and sensors as surplus, where a like-for-like keeps a loop on its existing installation.

Parts. Transmitters, electronics modules, display modules, housings and remote cables.

Installation parts. Earthing rings, gaskets, mounting kits and sun shields.

We tell you whether an item is new or surplus and whether it comes with calibration documentation.

The one habit worth adopting

Photograph every flow meter nameplate on the plant, sensor and transmitter both, and keep the images somewhere findable.

It costs an afternoon. It gives you the order codes for quoting, the serial numbers for identification, and the calibration values that make a transmitter swap safe. On a plant where flow measurements feed yield or product accounting, that is the cheapest insurance available.

Common questions

Can you get a part that is not listed on your site?
Usually. The site shows what we hold, not what we can source.

Can I just swap the transmitter?
Only if you enter the sensor's calibration data into it. Otherwise the meter reads confidently and wrongly.

Why is my magmeter reading noisy?
Earthing, nine times out of ten. Check earthing rings on lined pipe, flange straps and how close the signal cable runs to drive cables.

My Coriolis reads flow when the valve is shut.
Either the zero is wrong or the valve is passing. Zeroing has to be done full, at temperature, with genuinely no flow.

Can a Promag measure oil?
No. It needs a conductive liquid. That is a Promass or another principle.

Do you supply used flow meters?
Where the loop is not a quality or trade measurement, yes. Where it is, we would rather quote new and say why.

What is the lead time?
Configured meters are made to order. We give you a firm figure with the quote.

Do you quote in NZD?
Yes, in NZD including GST for New Zealand customers.

Send us both nameplates

Sensor and transmitter. They are two order codes and one measurement, and the calibration value on the sensor is the number that makes a swap safe. Quotes in NZD including GST.

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Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with Endress+Hauser. Endress+Hauser, Promag, Promass, Prowirl and Prosonic are trademarks of the Endress+Hauser Group. All trademarks, brand names and order codes are the property of their respective owners and are used here for identification purposes only.