Dragino LoRaWAN Analogue Input for ProSense 4–20 mA Pressure Level and Flow Instruments
A pressure transmitter on a remote tank is only useful if someone can see its reading before the pump runs dry, the filter blocks, or the line pressure drifts out of range. The problem is that many of the places that need measurement are the places where cabling is costly, awkward, or simply not planned for.
That is where a Dragino LoRaWAN analogue-input node and a ProSense 4–20 mA instrument make a practical pair.
ProSense pressure transmitters, level sensors, flow meters, and other loop-output devices are built for real industrial measurement. Dragino LoRaWAN hardware takes that field signal and sends it wirelessly to a gateway, then onward to a cloud platform, SCADA system, dashboard, or alerting service. The result is a clean path from physical process value to usable data, without trenching cable or adding a full PLC panel at every measurement point.
Why 4–20 mA still fits wireless monitoring
The 4–20 mA signal has lasted in industry because it solves real field problems. It runs over long cable distances, resists electrical noise better than many voltage signals, and gives a live zero. A reading near 4 mA means the measured value is at the bottom of the configured range. A reading near 20 mA means it is at the top. A reading near 0 mA often points to a broken loop, dead instrument, or wiring fault.
That makes 4–20 mA a strong match for wireless sensing. Dragino does not need to replace the instrument. It simply reads the analog loop and transmits the value.
This is useful when the plant already trusts ProSense instruments for measurements such as:
Pump discharge pressure
Tank level from a hydrostatic pressure sensor
Open channel or enclosed vessel level
Flow rate from a magnetic, turbine, or paddlewheel flow transmitter
Differential pressure across a filter
Vacuum level on process equipment
Water, wastewater, chemical, air, or hydraulic system monitoring
A wireless node is especially helpful when the measurement is important but not critical enough to justify conduit runs, cable trays, PLC input cards, and panel space. Many monitoring points fall into that middle ground. They matter, but they do not need a full control system rebuild.
How the Dragino node connects to a ProSense instrument
A typical setup has four parts:
A ProSense field instrument
A Dragino LoRaWAN analogue-input node
A field power source for the loop, if required
A LoRaWAN gateway within radio range
The ProSense device measures a real process condition. It converts that measurement into a 4–20 mA output. The Dragino node reads that current input. At the selected interval, it sends the reading over LoRaWAN.
The wiring depends on the instrument type.
Two-wire loop-powered transmitters
Many pressure transmitters and level transmitters use a two-wire loop-powered design. The same pair of wires carries power and the 4–20 mA signal.
A common loop looks like this:
Loop part | Role |
DC power supply positive | Feeds the transmitter loop |
ProSense transmitter | Varies current based on pressure, level, or flow |
Dragino analogue input | Measures loop current |
DC power supply negative | Completes the circuit |
In this arrangement, the Dragino input sits in series with the current loop, based on the wiring requirements of the chosen node. The node measures the loop current without needing to be the main power source for the instrument.
This setup works well for remote pressure and hydrostatic level measurements where a small field power supply is already available, or where a solar and battery system powers the loop.
Three-wire and four-wire instruments
Some flow meters, ultrasonic level transmitters, and process instruments need separate power and signal wiring. These may have:
Power positive
Power negative
Analog output positive
Analog output common
The instrument gets its own supply. The Dragino node reads the analog output between the correct signal and common terminals. This is often the cleanest setup when the instrument has a display, pulse output, relay output, or higher power electronics.
For these devices, check three things before installation:
The analog output is set to 4–20 mA, not 0–10 V or pulse only
The Dragino input type matches the output type
Signal common and power common are wired as required by the instrument manual
Some installations also add a local disconnect, surge protection, or fused loop supply. That is good practice in exposed outdoor locations and around pumps, motors, and long cable runs.
Field power matters as much as wireless range
The wireless link often gets the attention, but field power decides whether the installation is stable.
A 4–20 mA instrument needs enough voltage to power its electronics and drive the loop through the total resistance of the circuit. That includes the transmitter, cable, input resistance, and any protection devices. If the supply voltage is too low, the signal may saturate, drift, or never reach 20 mA.
Most industrial loops use a DC supply, commonly in the 12 to 24 V DC range, but the correct value depends on the specific ProSense instrument and the Dragino input arrangement. Always size the supply from the instrument documentation, not from habit.
There are three common power approaches.
Use an existing control power supply
If the site already has 24 V DC in a nearby panel, it can often power the ProSense transmitter loop. The Dragino node can then monitor the loop and transmit the reading. This is a strong choice for pump skids, packaged equipment, utility rooms, and treatment systems.
The benefit is reliability. The site power is already maintained, fused, and grounded.
Use a local plug-in or DIN rail supply
For a semi-permanent installation, a small local DC supply can feed the loop inside a junction box or enclosure. This works well when AC power is nearby but no signal cable returns to the control room.
The Dragino LoRaWAN node removes the need for the long analog cable run. The local supply handles only the field instrument.
Use battery or solar where no power exists
Many remote monitoring points have no practical power source. In these cases, battery or solar may work, but the design needs care. A loop-powered transmitter draws current continuously while powered. A wireless node also consumes energy when sampling and transmitting.
To save power, the system may wake the instrument, allow the reading to settle, sample the analog input, transmit, then return to a low-power state. Whether this is suitable depends on the sensor type, warm-up time, required reporting interval, and available sunlight or battery capacity.
For remote tanks, ponds, irrigation lines, and utility assets, this can be an excellent use case. The key is to select the ProSense instrument and Dragino hardware together so the power budget makes sense.
Scaling turns milliamps into real units
Raw current is not what operators want to see. They want PSI, feet, gallons per minute, inches of water column, or percent full.
Scaling converts the 4–20 mA value into the engineering unit that matches the ProSense instrument range.
The basic idea is simple:
4 mA equals the low end of the range
20 mA equals the high end of the range
Values between 4 and 20 mA scale linearly
For a ProSense pressure transmitter ranged from 0 to 100 PSI:
Loop current | Scaled value |
4 mA | 0 PSI |
12 mA | 50 PSI |
20 mA | 100 PSI |
For a level transmitter ranged from 0 to 10 ft of water:
Loop current | Scaled value |
4 mA | 0 ft |
8 mA | 2.5 ft |
12 mA | 5 ft |
16 mA | 7.5 ft |
20 mA | 10 ft |
This scaling can happen in different places. Some Dragino payloads may send raw input values that get decoded and scaled in the LoRaWAN network server or application. In other setups, the node configuration, decoder, or dashboard applies the engineering conversion.
The most important point is to keep the full measurement chain consistent:
ProSense instrument range
Analog output range
Dragino input configuration
LoRaWAN payload decoder
Dashboard display units
Alarm setpoints
A mismatch in any one of these can make a good sensor look wrong. For example, if a 0 to 200 PSI transmitter is scaled as 0 to 100 PSI in the dashboard, every displayed value will be half of the real pressure.
Reporting intervals should match the process
LoRaWAN is excellent for periodic measurement, alarms, and remote visibility. It is not meant to replace high-speed closed-loop control. The best installations choose a reporting interval that fits the process.
A storage tank may only need updates every 15 minutes, 30 minutes, or hourly. A pump discharge line may need more frequent reporting while the pump is running. A filter differential pressure point may be fine with slower reports and faster alerts when the value crosses a threshold.
Shorter reporting intervals give more detail, but they use more battery and more network airtime. Longer intervals extend battery life and reduce traffic, but they may miss short events.
Good starting points are based on how quickly the process changes:
Application | Practical reporting style |
Bulk tank level | Slower periodic reports, with high and low alarms |
Pump pressure | More frequent reports during operation |
Filter condition | Periodic reports with a high differential alarm |
Flow totalization support | Regular flow rate reports, with separate totalizer where needed |
Flood or sump level | Periodic reports plus urgent high-level reporting |
Remote utility pressure | Moderate interval trending with low-pressure alerts |
For battery-powered installations, avoid sending more often than the decision requires. If no one will act on a one-minute change, a one-minute interval may only shorten service life.
Some Dragino hardware also supports configuration options for confirmed or unconfirmed uplinks, sampling behavior, data logging, downlink settings, and alarm reporting. The right choices depend on how critical the message is and how the LoRaWAN network is managed.
Practical applications for Dragino and ProSense together
The value of this pairing is clearest in real facilities. ProSense provides the physical measurement. Dragino provides the wireless connection. Together, they turn isolated instruments into visible assets.
Remote tank level monitoring
A ProSense level sensor can measure liquid height in a tank, while the Dragino node reports the level to a dashboard. This helps with chemical totes, water storage, wastewater lift stations, agricultural tanks, and process feed vessels.
Common alerts include:
Low level before a pump loses suction
High level before overflow
Unexpected level drop
Refill required soon
This is often one of the fastest applications to justify because avoided site visits and emergency deliveries have clear value.
Pump and line pressure reporting
A ProSense pressure transmitter on a discharge line can show whether a pump is building pressure, whether a valve is closed, or whether a line has lost supply pressure. Dragino wireless reporting makes this useful in remote pump houses, irrigation zones, industrial yards, and utility sites.
Pressure trend data can also reveal conditions that operators might miss during manual rounds.
Flow meter visibility where no signal cable exists
Many flow meters and flow transmitters provide a 4–20 mA output for flow rate. Connecting that signal to a Dragino analogue-input node allows wireless reporting without running a long cable back to the main panel.
For totalized flow, use the flow meter’s own totalizer or a setup that properly counts pulses if total volume is required. A 4–20 mA signal is best for flow rate, while pulse outputs are often a better fit for accumulated volume.
Filter and strainer condition monitoring
Differential pressure is a simple way to track filter loading. A ProSense pressure or differential pressure instrument can send a 4–20 mA signal to a Dragino node. When the reading rises above the maintenance threshold, the system can flag the filter for service.
This helps avoid both premature filter changes and clogged-filter failures.
Temporary measurement during troubleshooting
Not every monitoring point needs to stay forever. A Dragino node and ProSense transmitter can be used as a temporary diagnostic kit. Install it on a line, trend the value for a few days or weeks, then move it to the next problem point.
That flexibility is one reason wireless analog monitoring is useful for maintenance teams, system integrators, and plant engineers.
What to specify before ordering
The best results come from selecting the instrument and wireless node as one system.
For the ProSense instrument, define:
Measurement type, such as pressure, level, or flow
Process range and engineering units
Wetted materials and process connection
Output type, especially 4–20 mA
Power requirement
Environmental rating
Cable, connector, or conduit needs
For the Dragino hardware, define:
Number of analog inputs needed
Input type, such as 4–20 mA
LoRaWAN regional band for the deployment area
Enclosure and mounting requirements
Power method
Reporting interval and battery expectations
Payload decoding and platform integration
This avoids common mistakes, such as buying a voltage-output instrument for a current-input node, selecting a transmitter range that is too wide for useful resolution, or choosing a reporting interval that drains a battery faster than expected.
A well-matched system is simple in the field. The instrument measures. The Dragino node reports. The platform displays the value in the right units.
The takeaway for industrial wireless analog monitoring
Dragino LoRaWAN hardware and ProSense 4–20 mA instruments make a strong combination for pressure, level, flow, and other remote measurements. The approach keeps proven industrial sensing at the process connection and adds wireless reporting where cable is expensive or inconvenient.
For the best installation, start with the physical measurement. Choose the right ProSense transmitter or meter for the process. Then match it to a Dragino analogue-input node with the correct input type, power plan, reporting interval, and LoRaWAN coverage.
That pairing gives you more than a wireless signal. It gives you practical visibility into real equipment, real fluids, and real operating conditions.
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