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Quick Answer: A remote electronic display backend for a magmeter moves the transmitter and display away from the flow sensor. This lets engineers read flow rate, total flow and faults from a panel or wall mount up to 100 m away. Silver Automation Instruments supplies electromagnetic flow transmitters with remote electronic display backends for DN15 through DN2000 lines with 4-20 mA HART, pulse and RS485 Modbus outputs.
Most electromagnetic flowmeters ship in two forms. A compact magmeter keeps the sensor and transmitter in one housing. A remote display backend splits the two. The sensor stays in the process line. The transmitter electronics sit in a separate panel or wall mount. A shielded signal cable links the sensor to the remote display.
Remote backends do not change the measuring principle. The meter still reads flow by detecting voltage across electrodes in a conductive liquid. The advantage is physical separation. You can put the sensor in a flooded pit or a hot zone. The display stays in a cool dry control room.
Silver Instruments builds remote backends with signal cable lengths of 5 m, 10 m, 20 m, 30 m and 50 m. Longer runs are available on request.
Here is the thing. Plant engineers usually select remote display magmeters for practical site reasons. The sensor location is hard to reach. The process temperature is high. Or the sensor sits in a hazardous area and the display must stay in a safe zone.
We have seen this on customer sites many times. A wastewater plant in Chile put a DN300 magmeter in a below grade concrete pit. The pit filled with rainwater during a storm. The remote display stayed dry in a cabinet 40 m away. The flow signal did not fail.
In another case a paint manufacturer in Vietnam needed a DN80 magmeter for solvent based product. The sensor area ran at 55 °C continuous. The wall mount display went into a corridor with normal room temperature. PT100 temperature sensors were also wired to the transmitter for process logging. The display showed flow rate in cubic meters per hour and total batch volume.
A remote display backend must send data to PLC DCS or local indicators. The standard output from Silver Instruments is 4-20 mA HART. This gives one analog signal plus digital diagnostics over the same pair of wires. For totalizing, a pulse output is common. Many water and wastewater sites also ask for RS485 Modbus RTU.
Because electromagnetic flowmeters require a minimum fluid conductivity, check your liquid before ordering. Most magmeters need at least 5 µS/cm. Some industrial units can work below 3 µS/cm but accuracy may shift. For high viscosity products like glucose or edible oil above 500 cP the meter still reads volume flow. The output remains stable because the magnetic field does not depend on viscosity.
Some heat metering versions accept PT100 inputs. The transmitter then calculates mass flow or heat flow when density is entered manually. You can get kg/h on the display for water based liquids. For chemicals check the density value supplied by your lab.
ATEX Zone 1 approval is available for remote display backends. The sensor and the local junction box can be rated for gas or dust zones. The remote display panel stays in a non hazardous area. This lowers cost and makes maintenance safer.
In practice the cable between sensor and remote display should be a single continuous shielded run. Avoid splicing. Ground the shield at one end only. Most engineers skip this part and then chase signal noise later. Use the cable length specified in the order. Do not cut a 30 m cable to 3 m unless you know the coil drive circuit can handle the impedance change.
Mount the remote display at eye level. If the display will be installed outdoors use a sun cover. A direct sunlight 45 °C day can make an LCD hard to read even when the ambient air is 35 °C.
Last year a customer in Vietnam asked us about a DN100 remote display magmeter for a wastewater discharge line. The pipe ran through a pit that was always damp. They ordered a flow sensor with a remote wall mount display and 20 m cable. The 4-20 mA HART signal went to a PLC. The plant now reads flow rate and total from the control room without entering the pit.
A seawater desalination plant in Saudi Arabia needed DN400 remote display magmeters for brine lines. The sensors were outside in 50 °C summer heat. The remote displays went into an air conditioned rack room. We supplied hard rubber liner and titanium electrodes. This combination handles chloride levels above 25 000 mg per liter.
A food grade producer in Malaysia uses DN15 remote display magmeters on a liquid sugar line. The flow range is 20 kg/h to 800 kg/h. The density of the sugar syrup is entered in the transmitter. The display shows both volume flow and mass flow. This avoids a separate flow computer.
Start with pipe size and flow range. Small lines from DN15 to DN50 often need low flow electrodes. Medium lines from DN80 to DN300 are straightforward. Large lines above DN350 need higher coil drive power. The remote backend stays similar across sizes but the sensor winding changes.
Pick a liner and electrode material based on your fluid. For clean water use hard rubber and 316L stainless steel. For seawater use hard rubber or PTFE with titanium. For chemicals use PTFE with Hastelloy or tantalum. For food grade use PTFE with 316L and a sanitary process connection.
Pick the output that matches your control system. 4-20 mA HART is the most common for process control. Pulse output suits batch totalizers. RS485 Modbus RTU fits sites with many meters and a SCADA system.
Remote display backends cost more than compact magmeters because of the extra cable and junction box. The price increase is usually 12 to 20 percent for standard cable lengths up to 30 m. Longer cables add more. ATEX certification also adds cost.
Do not buy only on price. A cheap remote cable can cause unstable readings. Ask for the cable capacitance per meter and the maximum allowed length. This data tells you if the backend is designed correctly.
Send us your pressure in bar, temperature in °C, pipe size in DN, and flow range. We will recommend a remote display magmeter with the right liner electrodes and output. You can reach Silver Automation Instruments at Tel +86-25-68650347, WhatsApp +86-25-52155837, or WeChat +86 15365082610. Our site is flow-meter.com.au.
What is the maximum cable length between a magmeter sensor and a remote display backend?
Standard lengths are 5 m, 10 m, 20 m, 30 m and 50 m. Some projects use 100 m with a signal booster. The allowed length depends on cable capacitance and fluid conductivity.
Can I upgrade an existing compact magmeter to a remote display backend?
Usually no. The sensor coil and electrode wiring are matched to the transmitter. A field conversion is rarely reliable. It is better to order a remote version from the start.
Which outputs are available on Silver Instruments remote magmeters?
You can choose 4-20 mA HART pulse output or RS485 Modbus RTU. Dual output versions are available. All outputs can be read from the remote display at the same time.
Do remote display magmeters work in ATEX Zone 1 areas?
Yes. The sensor and junction box can be rated for ATEX Zone 1 gas or dust. The remote display panel is mounted in a safe area. This keeps the electronics accessible during operation.
What information should I send to get a price?
Send pipe size DN fluid name pressure in bar temperature in °C and flow range. Also tell us if you need ATEX approval or a specific cable length. We will reply with a selection and price.
