Electromagnetic Flow Meter Selection Guide: Start With the Liquid, Not Just the Pipe Size
A purchase inquiry for a flow meter often starts with pipe size.
“Need flow meter for 4 inch line.”
That is useful information, but for an electromagnetic flow meter it is nowhere near enough.
What is flowing through that 4 inch line? Is it raw water, wastewater, an acidic solution, brine, fruit juice, paper pulp or another liquid? Is the liquid conductive enough for electromagnetic measurement? What lining will be in contact with it? Which electrode material can tolerate the process? Does the flow signal need to go to a PLC through 4–20 mA, RS485 or HART?
Those questions matter because an electromagnetic flow meter is selected around the process liquid as much as the pipeline.
The Radical TechArt AEFM-100 shown in the supplied Flow Meter catalogue is a microcontroller based, full bore electromagnetic flow meter designed for conductive liquids and slurries in closed pipes. The catalogue lists sizes from 15 mm to 500 mm, conductivity from 10 μS/cm, bidirectional measurement and several material and output configurations.
That gives buyers flexibility, but only when the meter is configured for the actual application.
What Is an Electromagnetic Flow Meter?
The AEFM-100 is designed to measure the volumetric flow of conductive liquids and slurries.
The product image on page 5 shows the meter as a flanged full bore instrument, while page 6 describes it as an obstructionless design with no conventional mechanical flow measuring components in the flow path.
The basic measurement depends on a magnetic field and the voltage induced by the conductive liquid moving through that field. The catalogue explains that the induced voltage is generated across the pipe section filled by the magnetic field.
For a plant engineer, the practical meaning is more important than the physics alone:
- There are no moving measurement parts in the flow path
- The liquid needs sufficient conductivity
- Lining and electrode selection become important
- The meter measures volumetric flow
- The catalogue states that measurement is independent of flow pressure, temperature, density and viscosity
This is why electromagnetic flow meters are very different from mechanical meters that depend on a rotor, turbine or other moving element.
The First Question: Is Your Liquid Conductive?
This should be checked before discussing output signal, display or even price.
The AEFM-100 catalogue specifies a minimum conductivity of 10 μS/cm.
If the process liquid does not meet the required conductivity, the meter should not simply be selected because the pipe size matches.
This is also why electromagnetic flow meters are particularly relevant to many water based and process liquid applications, but should not be treated as a universal flow meter for every fluid.
Before ordering, provide the actual liquid name and conductivity information when available.
Where the AEFM-100 Is Used
The catalogue gives a fairly broad application list, which makes the intended use of this meter much clearer than a generic flow meter specification sheet.
Applications listed on page 7 include:
- Raw water
- Portable water
- Sea water
- Waste water
- Heat exchanger applications
- Industrial and domestic effluent
- Syrup
- Molasses
- Fruit juice
- Pulp and beverages
- Acidic and alkaline solutions
- Cooling water
- Brine solutions
- Paper pulp
- Black, green and white liquor
- Neutral salts solutions
Page 6 also lists industries such as effluent treatment, water supply, food and drug, chemical and fertilizer, dairy, sugar, textile processing, petrochemical, pharmaceutical and metallurgy.
The useful point here is that these applications are not all chemically similar.
A meter for cooling water should not automatically be configured with the same lining and electrode material as one intended for an acidic process solution.
Why Lining and Electrode Material Matter
This is probably one of the most important selection points in the entire catalogue.
The AEFM-100 ordering information provides several lining choices:
| Lining Code | Material |
|---|---|
| L1 | Hard Rubber |
| L2 | Neoprene |
| L3 | PTFE |
| L4 | Polyurethane |
| L5 | PFA |
Electrode choices include:
| Electrode Code | Material |
|---|---|
| E1 | SS 316L |
| E2 | Hastelloy C |
| E3 | Titanium |
| E4 | Tantalum |
The catalogue specifically notes that corrosion and abrasion resistance can be achieved by selecting suitable wetted materials, particularly the lining and electrode.
Why this matters in actual plant conditions
Imagine two customers asking for the same DN50 electromagnetic flow meter.
Customer A is measuring cooling water.
Customer B is measuring an acidic solution.
The line size may be identical, but the process compatibility requirement may not be.
This is where buying by model size alone becomes risky.
Before finalizing the flow meter, confirm:
- Exact process liquid
- Chemical concentration, where relevant
- Normal and maximum temperature
- Abrasive solids, if present
- Required lining
- Required electrode material
Material compatibility should be confirmed for the actual process before the final configuration is ordered.
Radical TechArt AEFM-100: Key Specifications That Actually Affect Selection
The catalogue provides the following main technical details for the electromagnetic flow meter.
| Parameter | Catalogue Specification |
|---|---|
| Nominal diameter | 15 mm to 500 mm |
| Process pressure | 16 kg/cm² |
| Minimum conductivity | ≥10 μS/cm |
| Response time | 0.3 second |
| Empty pipe detection | Yes |
| Environment temperature | 0°C to 55°C |
| Measuring tube material | SS 304 / SS 316 |
| Sensor housing material | MS / SS 304 / SS 316 |
| Connection | Flange ANSI 150 |
| Internal lining | PTFE / Rubber in technical table |
| Electrode material | SS 316 / Hastelloy C / Titanium / Tantalum |
| Process temperature | PTFE: 150°C |
| Display version | Remote / Integral |
| Processor | ARM Microprocessor |
| Electronic housing | Die cast aluminium, IP65 |
| Display | LCD, multiple information |
| Power supply | 230 V AC or 24 V DC |
| Output | 4–20 mA isolated / RS485 / Pulse / HART |
| Remote cable | Standard 10 m |
| Measuring range | 0.2 to 12 m/s, bidirectional |
| Accuracy | ±0.5% listed in technical table |
| Repeatability | ±1% of span |
| Transmitter protection | IP67 |
There is one specification worth flagging rather than hiding.
Page 6 lists accuracy as ±0.5% of measured value, while the characteristics section on page 8 refers to ±0.3% to ±0.5% for acidic, alkali and neutral salt solutions with proper lining. Final accuracy for the ordered configuration should therefore be confirmed from the applicable datasheet or quotation.
Integral or Remote Display: Which One Makes More Sense?
The catalogue provides both integral and remote display versions.
The illustrations on page 7 show the difference clearly. In an integral configuration, the transmitter sits directly on the meter. In a remote arrangement, the sensor remains in the pipeline while the transmitter is installed separately.
Integral version
It keeps the installation compact because the electronics stay with the sensor.
Remote version
The catalogue specifies a standard remote cable length of 10 metres, while its ordering code shows cable options of 10, 20, 30, 50 and 80 metres.
Before ordering a remote unit, confirm the required cable distance rather than estimating it after installation.
4–20 mA, RS485, Pulse or HART?
The AEFM-100 provides several options for connecting flow measurement to an automation system.
4–20 mA
This is useful when instantaneous flow needs to be transmitted to an analog input on a PLC, controller, recorder or monitoring system.
The catalogue specifies an isolated 4–20 mA output.
Pulse
Pulse output is relevant when flow needs to be counted or totalized by compatible equipment.
This can be useful for batch quantities, consumption monitoring or flow totalization depending on the final system.
RS485
RS485 gives a digital communication option.
Do not stop at the word RS485 when specifying the meter. The exact communication protocol and register information should be confirmed before PLC or SCADA integration.
HART
HART is also listed as an available output option in the technical specification and ordering code.
For a project engineer, the output decision should be made from the control architecture, not from whichever version happens to be available first.
Empty Pipe Detection Is More Useful Than It Sounds
The catalogue includes empty pipe detection and states that empty or full pipe condition can be detected using capacitance technology.
Why does that matter?
An electromagnetic flow meter is intended to measure a liquid filled pipe. If the measurement tube is not properly filled, the flow reading may no longer represent the actual process condition.
Empty pipe detection gives the system another piece of information instead of treating every abnormal reading as real flow.
This can be particularly useful in water lines, transfer systems and processes where pipelines may periodically drain.
Forward and Reverse Flow Measurement
The brochure states that the AEFM-100 can measure both forward and reverse flow and lists a bidirectional measuring velocity range of 0.2 to 12 m/s.
That matters in systems where flow can genuinely reverse rather than always travelling in one direction.
The display features described in the catalogue also include flow rate, velocity, total flow, empty line and direction indication.
Flow Range: Check the Actual Process, Not Only the DN
Page 7 provides flow ranges from DN15 through DN500.
A few examples show how significantly capacity changes with pipe diameter:
| Meter Size | Catalogue Flow Range | Listed Accuracy Range |
|---|---|---|
| DN15 | 0.19 to 6.35 m³/h | 0.3 to 3.2 m³/h |
| DN25 | 0.52 to 17.66 m³/h | 0.7 to 8.8 m³/h |
| DN50 | 2.12 to 70.65 m³/h | 2.8 to 35 m³/h |
| DN100 | 8.48 to 282 m³/h | 11 to 140 m³/h |
| DN200 | 33.91 to 1130 m³/h | 45 to 560 m³/h |
| DN500 | 211 to 7065 m³/h | 280 to 3500 m³/h |
The brochure identifies the wider flow range with velocity from 0.3 m/s to 10 m/s and provides a separate accuracy range based on 1 m/s to 6 m/s.
That distinction is important.
A pipeline may physically accept a particular DN meter, but the normal operating flow should also be checked against the range where the desired measurement performance is expected.
Installation: Leave Enough Straight Pipe
The installation diagram on page 6 specifies:
where D represents the flow meter diameter.
This should be considered during planning, not after the meter arrives at site.
If a DN100 meter is being installed in a crowded skid with an elbow immediately before the instrument, simply having enough flange to flange space does not mean the installation is ideal.
Before ordering, check:
- Available upstream straight length
- Available downstream straight length
- Nearby elbows
- Valves
- Pumps
- Reducers
- Actual mounting position
The physical location is part of flow meter selection.
Why No Moving Parts Can Reduce Maintenance
Page 8 highlights a major characteristic of the AEFM-100: no moving parts.
It also states that there is no pressure drop caused by choked flow components.
This can be useful in applications involving wastewater, pulp or other process liquids where mechanical components in the flow stream could increase maintenance requirements.
It does not mean the meter requires zero maintenance under every process condition. Correct grounding, electrode condition, lining compatibility, installation and process buildup still matter.
But there is no turbine or mechanical rotor to maintain inside the measuring section.
Common Selection Mistakes
| Common mistake | Better approach |
|---|---|
| Selecting only from pipe size | Confirm liquid, conductivity and actual flow range |
| Ignoring conductivity | Verify that the liquid meets the required conductivity |
| Using the same lining for every chemical | Select lining according to process compatibility |
| Ignoring electrode material | Match electrode material to the liquid |
| Choosing output after installation | Decide PLC, SCADA and totalizing requirements before ordering |
| Ignoring straight pipe requirement | Plan for 10D upstream and 5D downstream |
| Assuming every DN gives the same useful velocity range | Check actual flow against the catalogue range |
| Ordering integral display for an inaccessible location | Consider remote display |
| Assuming any RS485 device connects directly to any PLC | Confirm protocol and communication details |
| Ignoring pipe filling condition | Consider installation and empty pipe detection |
Quick Selection Checklist
Before asking for an electromagnetic flow meter quotation, provide:
- Process liquid
- Conductivity, if known
- Pipe size
- Minimum flow
- Normal flow
- Maximum flow
- Process temperature
- Maximum pressure
- Required lining material
- Required electrode material
- Integral or remote display
- 230 V AC or 24 V DC power
- Required 4–20 mA, pulse, RS485 or HART output
- Required cable length for remote installation
- Available upstream and downstream straight pipe
- PLC or SCADA integration requirement
A message containing these details is far more useful than simply asking for an “electromagnetic flow meter price.”
Specifications to Confirm Before Purchase
The supplied catalogue provides substantial configuration information, but the following should still be confirmed for the final ordered meter:
- Exact chemical compatibility of lining
- Exact electrode compatibility
- Final accuracy for the selected configuration
- Process temperature for the chosen lining
- Grounding and earthing requirement
- Earthing ring requirement
- RS485 protocol details
- HART configuration
- Pulse output characteristics
- Exact flange dimensions
- Calibration certificate requirement
- Display configuration
- Engineering units
- Remote cable requirement
- Site IP requirement
- Any hazardous area requirement
The catalogue ordering code also provides options for flange material, lining, electrode, earthing ring, measuring tube, coil housing, cable length and output, so these should be treated as part of the application selection rather than as optional paperwork after the meter has been chosen.
Why Buy an Electromagnetic Flow Meter from Radical TechMart?
An electromagnetic flow meter should not be selected from DN and price alone.
The process liquid, conductivity, flow velocity, electrode, lining, output signal and installation arrangement all affect the final choice.
At Radical TechMart, the useful part of the buying process is helping customers work through those parameters before the meter reaches the site.
That is especially relevant for water treatment plants, OEMs, process industries, EPC contractors, system integrators and maintenance teams that may need the flow meter connected to a PLC, SCADA system, totalizer or plant monitoring network.
Final Thoughts
The Electromagnetic Flow Meter becomes a strong option when the application involves a suitable conductive liquid or slurry and the plant wants full bore flow measurement without moving measurement parts in the flow path.
For the Radical TechArt AEFM-100, the supplied catalogue highlights a 15 mm to 500 mm size range, minimum conductivity of 10 μS/cm, bidirectional flow measurement, multiple lining and electrode materials, integral or remote display, empty pipe detection, and 4–20 mA, RS485, pulse and HART output options.
But the most important part of the selection is not finding a meter that fits between two flanges.
It is finding the configuration that fits the liquid flowing through them.
FAQs
1. What liquids can an electromagnetic flow meter measure?
The AEFM-100 is specified for conductive liquids and slurries in closed pipes. Its catalogue applications include raw water, wastewater, sea water, cooling water, brine, syrup, molasses, fruit juice, pulp, acidic and alkaline solutions and neutral salt solutions.
2. What minimum conductivity does the AEFM-100 require?
The catalogue specifies a minimum conductivity of 10 μS/cm.
3. What sizes are available?
The AEFM-100 range covers nominal diameters from 15 mm to 500 mm.
4. Can this electromagnetic flow meter connect to a PLC?
Yes, the catalogue provides 4–20 mA, RS485, pulse and HART output options. Exact PLC communication and signal requirements should be confirmed before ordering.
5. Is the AEFM-100 available with a remote display?
Yes. Both integral and remote versions are listed. The standard remote cable is 10 metres, with additional cable length options shown in the ordering code.
6. Does an electromagnetic flow meter create pressure drop?
The AEFM-100 catalogue describes the meter as having no choked flow parts and states that there is no pressure drop from such obstructions.
7. Can it measure reverse flow?
Yes. The catalogue lists bidirectional measurement and specifically states that both forward and reverse flow can be measured.
8. How much straight pipe is required?
The catalogue installation diagram shows 10D upstream and 5D downstream. The actual installation should be checked against the final meter size and piping layout.
