Industrial RS485 Modbus to LoRaWAN® Converter

An RS485 to LoRaWAN converter puts wired Modbus equipment on a wireless network. The MacSync LX1 acts as the Modbus RTU master, polls the registers of energy meters, flow meters, drives, PLCs and sensors over RS485, and sends the values over LoRaWAN® to a gateway and on to your dashboard or SCADA. The equipment stays as it is; only the communication cable to the control room goes.

Yes, but not as a cable replacement. A LoRaWAN® message is small and a device at long range sends only a few of them an hour, so a SCADA master cannot poll a slave through the air the way it does on a wire. An RS485 to LoRaWAN converter solves this by polling locally: the MacSync LX1 sits beside the equipment as the Modbus RTU master, reads the registers on its own schedule and sends only the values. Your software then takes the readings from the network server instead of from the Modbus bus.

A master. It sends the Modbus RTU requests, and your meter, drive or PLC answers as a slave on its existing address. That is the role a retrofit needs, because almost every meter and drive is a slave waiting to be polled. It does not answer as a slave itself, so a PLC cannot poll it.

Wire the meter’s RS485 A and B terminals to the MacSync LX1. In the Maya app, set the baud rate and parity to match the meter, then add a field for each value you want: the meter’s slave ID, the function code, the register address and the data type from its Modbus manual. Read the live value in the app to confirm it, and the readings then arrive over LoRaWAN®. The same steps apply to a flow meter, a drive or a PLC.

Any device that answers as a Modbus RTU slave on RS485, whatever its make: multifunction energy meters, water, gas and flow meters, variable frequency drives, PLCs and RTUs, solar inverters, DG set controllers, and sensors with an RS485 output. If you send us the model, we will check its register map and serial settings before you order.

Four: Read Holding Registers (03), Read Input Registers (04), Write Single Register (06) and Write Multiple Registers (16). Function code 03 reads holding registers, which a device also lets you write, and 04 reads input registers, which are read-only measurements; a meter manual says which one each value uses. Codes 06 and 16 let a downlink change a setpoint or send a command. The converter is always the Modbus RTU master, so the connected equipment needs nothing beyond its existing slave address and serial settings.

No. In the Maya app each value is a field with a slave ID, a function code, a register address, a data type and a register count, and the converter builds the Modbus RTU request, CRC included, from those entries. There are no hex command strings and no AT commands to compose, which is where most of the set-up time goes on converters that are configured with raw frames.

From 1,200 to 115,200 bps, with 8 data bits, none, even or odd parity and 1 stop bit, on half-duplex RS485. Every device on the bus must use the same baud rate and parity, and each needs its own slave ID between 1 and 247. The settings are made in the Maya app over Bluetooth and can be changed later by downlink.

The MacSync LX1 has one RS485 port and polls several Modbus RTU slaves wired to the same two conductors, each identified by its slave ID. The RS485 standard allows 32 standard unit loads on one segment, and Modbus addresses run from 1 to 247. In practice the limit is set less by the bus than by how many registers you want in each report, because a LoRaWAN® uplink is small. Send us the device list and the registers and we will confirm how it maps.

The LoRaWAN® radio sets the ceiling, on every vendor’s converter. On IN865 and EU868 the maximum application payload is 51 bytes at the longest-range settings (SF10 to SF12), 115 bytes at SF9 and 222 bytes at SF7 and SF8. A 16-bit register takes 2 bytes and a 32-bit value 4 bytes, so at the longest range there is room for about 25 sixteen-bit registers at the very most, and fewer once header bytes are counted. As a planning figure, allow for about 15 sixteen-bit registers per uplink at the longest range and about 35 at SF9. Report only what you need, send slow-changing values less often, and split a long register list across uplinks.

Yes. Every field has its own slave ID and starting address, so the registers do not have to be consecutive or on the same device: voltage from one block, energy from another and a value from a second meter are simply three fields. Where the registers you need do sit together, one field reads a group of up to 125 in a single request. High addresses are not a problem either, because the address range runs from 0 to 65,535.

Yes. The supported data types are INT16, UINT16, INT32 and FLOAT32. A 32-bit value occupies two registers, and meters differ in which register comes first, so the MacSync LX1 offers both orders for INT32 and FLOAT32: most significant word first or least significant word first. If a float reads as a nonsense number, the word order is usually the reason; switch it in the Maya app and read the live value again.

Yes, published on GitHub in the Macnman decoder repository: one codec file each for The Things Stack, ChirpStack v4 and Milesight gateways, each with the uplink decoder and the downlink encoder, plus a stand-alone encoder. The link is in the downloads section. Added as the codec in ChirpStack or as the uplink payload formatter in The Things Stack, it turns each register into a named value with its data type, and each uplink carries the battery level and a UTC timestamp.

Yes. A downlink from the network server can write holding registers or coils on a slave, so you can change a setpoint or switch an output. Other downlinks add a register to the polled list, change the baud rate and parity, or read a register once. Timing depends on the LoRaWAN® class. In Class A, the default, a downlink is delivered after the next uplink. In Class C the receiver stays open and the command arrives straight away, which needs the 9–36 V DC variant. LoRaWAN suits monitoring and occasional commands, not closed-loop control.

Yes. A one-time read is a downlink on FPort 13 that names the slave ID, the function code, the data type, the register count and the address; the converter polls that register and reports the result without adding it to the regular list. A downlink on FPort 15 returns a field that is already configured, which is a quick way to check the register list from the server.

That is LoRaWAN® Class A, the default. To save energy a Class A device listens only in two short windows straight after each uplink, so the network server holds a queued command until the converter next transmits. Shorten the reporting interval while you commission, or run the 9–36 V DC variant in Class C, where the receiver stays open and a write is delivered straight away. If no downlink arrives at all, check that the gateway is online and that the server’s downlink queue is not full.

It is often called a Modbus to LoRaWAN gateway, but it is not a gateway. The MacSync LX1 is an end device: it reads your Modbus equipment and transmits to a LoRaWAN® gateway, which forwards the data to a network server. You need a gateway in range, your own or a public network, and one gateway typically serves many converters across a site. The exception is a MacTalk version, where two Macnman devices talk directly with no gateway.

No, that is the opposite direction. The MacSync LX1 takes Modbus data to LoRaWAN®. Feeding readings from LoRaWAN sensors into a PLC, a BMS or SCADA is done on the network side, by a LoRaWAN to Modbus gateway or by an integration from the network server. If your software accepts MQTT or HTTP, the network server delivers the decoded readings to it directly.

An RS485 to LoRa converter is usually a transparent radio modem, often called a DTU: two units replace a cable, with no network, no server and no cloud. An RS485 to LoRaWAN converter joins a managed network through a gateway, so many devices report to one platform with encryption and central configuration. The MacSync LX1 is the second kind; its MacTalk version covers the point-to-point case when one meter only needs to reach one controller.

The names overlap. A bridge or converter reads Modbus RTU and forwards the values over LoRaWAN®; a data logger also keeps readings on the device. The MacSync LX1 polls and uplinks in every version, and variants with onboard memory buffer readings while the network is down. Tell us whether you need that buffer when you order.

It can. RS485 itself carries only data on its two wires, so power is always a separate matter. The MacSync LX1 has a selectable power output for the connected sensor, with a warm-up time of 0 to 2,000 ms before each poll, so an RS485 level or weather sensor is switched on, read and switched off again. Check the output level against the sensor’s supply voltage in its datasheet. Equipment with its own supply, such as an energy meter or a PLC, only needs the two RS485 wires.

As a reference, the 19 Ah battery variant lasts about 8 years reading a meter or PLC that has its own supply and sending one uplink an hour at SF7. Reporting more often, or a link that needs a higher spreading factor, shortens that: on a typical SF10 link the estimate is about 7.5 years at hourly reporting, about 5.5 years every 15 minutes and about 3.5 years every 5 minutes. A sensor that the converter energises before each poll takes more, about 3 years at 15 minutes on SF10. The battery-life table on this page gives the full set with its assumptions; these are estimates, not guaranteed figures. Where a supply exists, choose the 9–36 V DC variant.

Yes. The 19 Ah cell plugs into the board on a connector. Open the bottom of the enclosure, slide the board out, unplug the old cell, fit a new one of the same type and voltage with the polarity the right way round, and close the unit again. The steps are in the user manual.

Order the 9–36 V DC variant, MacSync-L-PV-X1 (SKU 83300), for meters and PLCs inside a powered panel, for short polling intervals and for Class C downlinks. Order the battery variant, MacSync-L-BV-X1 (SKU 83301), for flow meters, water meters and sensors with no supply nearby. MacTalk versions (SKU 83303 battery, 83302 DC) link two devices with no gateway, and a Bluetooth-only version (SKU 83304) is for local logging.

Around 2 km through a built-up site and up to 8 km with a clear line of sight, from the internal antenna at 23 dBm. Real range depends on the gateway antenna height, buildings and terrain, so plan gateway positions with a site survey or the gateway and coverage calculator. The Maya app’s network test shows the signal strength at the mounting point before you fix the unit.

An RS485 bus runs to about 1,200 metres at 9,600 bps on twisted-pair cable, and less as the baud rate rises. Fit a 120 ohm resistor at each end of the main run, keep branch stubs short, and wire A to A and B to B throughout; some makers label the terminals D+ and D− or swap the A and B convention, so check the manual. On a long or noisy bus, bias resistors hold the line in a defined state while no device is driving it; many meters and masters include them, so add external ones only if errors appear on an idle line. In most retrofits the converter sits within a few metres of the meter, so cable length is rarely the limit.

A successful join proves only the radio side; the Modbus side is checked separately. Check six things, in order of how often they are the cause. First, the A and B wires are swapped; reverse them. Second, the slave ID in the converter does not match the device. Third, the baud rate or parity differs. Fourth, the register address is off by one: many manuals number holding registers from 40001, while the protocol counts from zero. Fifth, the function code is wrong, reading a holding register as an input register or the reverse. Sixth, where the converter powers the sensor, the warm-up time is too short for the sensor to wake before it is polled. The Maya app shows the live value over Bluetooth, so each fix can be tested on the spot.

First, that the converter and the gateway are on the same frequency plan, IN865 in India. Second, that the DevEUI, AppEUI and AppKey on the network server match the device exactly; scanning the QR code in the Maya app avoids typing errors, and a MIC mismatch error means the keys differ. Third, that the gateway is online and the join requests are reaching the server. Joining is also quicker and more reliable at SF7 to SF10 than at SF12. The Maya app’s network test then sends a confirmed uplink and shows the signal strength.

Yes. It is a standard LoRaWAN® v1.0.4 device with OTAA activation, so it joins ChirpStack, The Things Network, Orbiwise, Netmore or a private server. Registration is by scanning the QR code shown in the Maya app, or by copying the DevEUI, AppEUI and AppKey. With the published decoder added on the server, each register appears as a named value.

On site, with the Maya app over Bluetooth: Modbus settings, register fields, reporting mode, triggers and LoRaWAN® settings, with no code and no cable. Later changes, such as the interval, the register list or the baud rate, can be sent as downlinks from the network server. Firmware is updated over the air from the app.

No. The MacSync LX1 is a Modbus RTU master on RS485. A Modbus TCP device speaks over Ethernet and an RS232 device uses a different electrical interface, so each needs its own converter to RS485 Modbus RTU first. Most meters, drives and PLCs offer an RS485 Modbus RTU port as standard or as an option.

Not directly. The RS485 port of the MacSync LX1 speaks Modbus RTU; DLMS/COSEM, the protocol on most utility smart meters in India, is a different protocol and is not on the datasheet. Two routes work. Read a multifunction panel meter with a Modbus RTU port on the same feeder, or put a DLMS to Modbus converter in front of the MacSync LX1 so that the meter’s values appear as Modbus registers.

Yes, in analog mode. The MacSync LX1 has two switchable channels, each set to 4–20 mA, 0–10 V or digital input, with 12-bit analog resolution. RS485 and the analog channels share the terminals, so a unit runs in RS485 mode or in analog mode, not both at once; a site with both kinds of instrument needs one unit for each. For analog-only work, see the MacSync LX1 analog to LoRaWAN converter page.

A LoRaWAN® version needs a gateway, and the gateway needs a path to the network server, which can be a private server on your own network with no internet. A MacTalk version needs neither: it sends the reading directly to another Macnman device, such as a MacSet controller, over a LoRa link.

Wired Modbus TCP gives the fastest updates and suits new installations where cable trays are already open. A GSM, 4G or NB-IoT RS485 modem needs no gateway but needs a SIM card, a data plan and operator coverage at every device. LoRaWAN® needs one gateway and then has no subscription per device and kilometres of range, which is why it suits retrofits across a spread-out site where new cable is the expensive part. For second-by-second control, stay wired; for readings every few minutes from equipment that is awkward to reach, LoRaWAN is usually the lowest-cost route.

Technically, yes. An electromagnetic or ultrasonic flow meter with an RS485 Modbus output gives its flow rate and totaliser, and a piezometer or level sensor with RS485 gives the water level. The battery variant suits a borewell with no supply and powers the level sensor only while it is read. Whether a telemetry system satisfies the conditions of a groundwater NOC, such as those set by the CGWA, depends on the reporting format the authority asks for, so confirm that with your consultant before you order.

On the figures their manufacturers publish, the Dragino RS485-LN, the Milesight UC100 and the RAK7431 are DC-powered bridges for inside a panel: the UC100 is IP30 and the RAK7431 is IP31, and they are configured over a USB cable or with AT commands. Dragino’s battery model is the RS485-LB, IP67 with an 8,500 mAh cell. The MacSync LX1 comes as a 19 Ah battery variant or a 9–36 V DC variant in an IP65 enclosure, is set up from a phone app, and is made in India for IN865. The comparison table above gives the figures, and the full comparison page lists the sources.

It ships on IN865, the 865 to 867 MHz plan used for LoRaWAN® in India, and the radio is WPC compliant. The MacSync LX1 is designed and manufactured by Macnman Technologies in Pune and is RoHS conformant. The same hardware is available on RU864, EU868, US915 and AU915 for other regions.

On a wall, stick the reference tape from the box where the unit will go, drill on its two marks and screw the bracket on; the converter slides down into the bracket until it locks. On a pole, thread plastic or stainless steel zip ties through the mounting clip and pull them tight around the pole. Either way the unit sits within a few metres of the meter, so the RS485 cable stays short.

Macnman hardware carries a two-year limited warranty against manufacturing defects from the invoice date; the non-rechargeable battery is a consumable and is not covered. In the box are the MacSync LX1, a mounting clip, mounting screws, a user manual and a warranty card. The IP68 cable extender and the power adapter are ordered separately.