Part of: Field tools

Poll Modbus devices from your Mac.
Native app. No Parallels.

Modbus TCP and RTU, master and slave, read and write, with built-in device simulators, in one native app. No VM, no Python scripts.

Download on theApp Store Buy Direct · $19.99 See what it does

Also for Windows 10 and 11: Download for Windows, free with limits, Pro $19.99.

$19.99

One-Time

TCP + RTU

Protocols

6+ Devices

Templates

macOS

Apple Silicon and Intel

Modbus Poll screenshot: live float32 meter registers polled over Modbus TCP, with a communication log underneath. — Live float32 meter registers polled over Modbus TCP, with a communication log underneath.

Modbus Poll screenshot: a live chart of three registers showing a step in load, with 30 second, 1 minute and 5 minute windows. — A live chart of three registers showing a step in load, with 30 second, 1 minute and 5 minute windows.

Modbus Poll screenshot: the traffic view decodes each request and response with function code, address range and register words. — The traffic view decodes each request and response with function code, address range and register words.

Demo video

Watch the demo

A tour of Modbus Poll for Mac: live register polling, a built-in slave simulator, decoded traffic, trends and an RS-485 bus scan.

Chapters

Watch on YouTube

Features

Poll, simulate, capture. One app.

TCP and RTU, master and slave, read and write, traffic capture, trend charts and device templates in one app.

Modbus TCP

Connect to any Modbus TCP device over Ethernet or Wi-Fi. Configure IP, port, and unit ID. Poll at a custom interval.

Modbus RTU (Serial)

Communicate over USB-to-RS485 and other USB serial adapters that appear as a serial port on your Mac. Configurable baud rate, data bits, parity and stop bits.

Read + Write

All function codes: FC01–FC06, FC15, FC16. Read and write coils and holding registers, read discrete inputs and input registers. 16-bit signed and unsigned, 32-bit signed and 32/64-bit float values, with big, little and swapped word order.

Master (Poll) Mode

Read blocks of coils, discrete inputs, holding registers or input registers from a device and watch live values in a table with real-time updates.

Slave (Server) Simulation

Simulate a Modbus slave device to test your master without physical hardware. Load device templates with realistic register maps and auto-simulated live data.

Traffic Capture & Export

Record every Modbus frame, request and response, with timestamps, delta times, and full hex decode. Filter by direction (TX/RX), expand any frame for detail, export to CSV for your network team.

Live Trend Charts

Pin any register to a live-updating chart. Monitor voltage drift, power spikes, or temperature changes over time, multiple series on one chart with pan and zoom. No external tools needed.

Communication Logging

Full request/response logging with millisecond timestamps. Debug timing issues, malformed frames, and timeout problems. Export logs for analysis.

Device Template Library

Load pre-built profiles for real devices, Schneider PM5560, SMA inverters, ABB analyzers. Registers auto-populate with correct addresses, units, and realistic simulated values. Create your own templates for any device.

Windows

Also on Windows 10 and 11. Download it free.

The same open source app, built for Windows 10 and 11 (x64 and ARM64). It is free to use with limits. Pro is $19.99 one-time, paid by card, and unlocks the rest.

Windows x64

Intel and AMD PCs. If you are not sure, pick this one.

Installer (.exe) Portable (.zip)

Windows ARM64

Windows on Arm devices, for example Snapdragon laptops.

Installer (.exe) Portable (.zip)

Version 1.3.6. SHA256SUMS.txt Release page on GitHub

The installers are not code-signed. The first time you run one, Windows SmartScreen shows "Windows protected your PC". Click More info, then Run anyway. You can compare the file's SHA256 with SHA256SUMS.txt before you run it. Step by step.

Free

Read values over Modbus TCP, with these limits:

Up to 20 polled values
1 saved connection profile
1 open connection

Pro for Windows, $19.99 one-time

Everything in Free with the limits removed, plus:

Write registers and coils
Poll more than 20 values
Slave simulator with device templates
Modbus RTU over serial, with bus scan and auto-detect
Live trends
Network scan
Several connections in tabs
CSV value logging
Multiple saved profiles
Traffic log export
CSV import and export of blocks

Buy Pro for Windows · $19.99

Card payment through Polar. Your key appears in the Voltrus Console after checkout. The app activates it online once.

One licence, Mac and Windows. Bought the Mac licence on voltrus.id? Use the same key on Windows. One device at a time; move it any time from your console. Purchases made in the Mac App Store have no key we can check, so they are separate. A Windows Pro key does not unlock the Mac app. One-time licenses can be refunded within 14 days, see the refund policy. More detail on the Modbus Poll for Windows page.

Screenshots

See it in action

Modbus Poll screenshot: a built-in Modbus slave running a power meter template with live values and a register log. — A built-in Modbus slave running a power meter template with live values and a register log.

Modbus Poll screenshot: modbus RTU over a USB serial port with a bus scan listing the unit IDs that answered. — Modbus RTU over a USB serial port with a bus scan listing the unit IDs that answered.

On iPhone and iPad

On the App Store. The same app, laid out for a phone and a tablet.

Modbus Poll screenshot: live meter values in a table on iPhone. — Live meter values in a table on iPhone.

The connection screen with host, port, unit ID and a saved profile.

Modbus Poll screenshot: the poll log with round-trip times on iPhone. — The poll log with round-trip times on iPhone.

Modbus Poll screenshot: the built-in Modbus slave with its register table on iPhone. — The built-in Modbus slave with its register table on iPhone.

Modbus Poll screenshot: a live trend chart of three registers on iPhone. — A live trend chart of three registers on iPhone.

Modbus Poll screenshot: live meter values and the log on iPad. — Live meter values and the log on iPad.

Modbus Poll screenshot: the connection screen alongside the register table on iPad. — The connection screen alongside the register table on iPad.

Modbus Poll screenshot: the built-in Modbus slave and its live values on iPad. — The built-in Modbus slave and its live values on iPad.

Modbus Poll screenshot: decoded request and response traffic on iPad. — Decoded request and response traffic on iPad.

Modbus Poll screenshot: a live trend chart of three registers on iPad. — A live trend chart of three registers on iPad.

Compare

How it compares to what you're using now

The two usual workarounds on a Mac, side by side.

Price

$19.99 one-time

Paid app + Parallels + Windows

Free

Native macOS

Yes: Apple Silicon

No: Windows VM

Yes (Python)

Modbus TCP

Yes

Modbus RTU (Serial)

Yes: USB serial adapters

Yes

Yes (Python)

Read + Write (FC01–FC06, FC15, FC16)

Yes

Master (Poll) Mode

Yes

Slave (Server) Simulation

Yes: included

Separate app (Modbus Slave)

Code required

Device Templates (PM5560, SMA, ABB)

Yes: auto-drifting values

No: manual setup

Not built in

Traffic Capture + CSV Export

Yes

Yes: traffic monitor, text/Excel logging

Not built in

Live Trend Charts

Yes: multi-series, pan/zoom

Yes: real-time charting

Not built in

GUI

Native macOS app

Windows only

Library / command line

Installation

App Store: one download

Buy app + VM setup

pip install

Subscription

None: one-time

Parallels subscription

None

Use Cases

Built for field engineers who carry MacBooks.

Power meter commissioning, solar plants, SCADA integration, bus debugging. Modbus is everywhere, and now you can poll and simulate it natively on your Mac.

PWR

Power Meter Commissioning

Connect to Schneider PM5560 and similar power meters. Verify phase voltage, current, active and reactive power, power factor, and energy totals before energizing the switchgear.

SOL

Solar Plant Commissioning

Poll SMA STP 60-US-10 inverters over Modbus TCP. Read daily yield, DC string voltage and current, grid frequency, and status flags from your MacBook on the site network.

SIM

Factory Acceptance Testing

Run slave mode with a device template and let your SCADA or HMI poll a simulated PM5560 or inverter. Run the FAT without physical hardware, in front of the customer.

BUS

RS-485 Bus & Network Debugging

Device not responding? Capture every frame with millisecond timestamps, filter TX/RX, expand for hex detail, and export to CSV. Hand the file to the network team.

INT

SCADA / HMI Integration

Verify register addresses and function codes before PLC wiring. Catch the holding-register 40001 vs protocol-address 0 off-by-one, and the FC03 vs FC04 mix-up, before they break commissioning day.

DEV

Embedded & Firmware Development

Building a Modbus slave device? Point the master at it, exercise every function code, and watch exception responses in the traffic log. Validate your register map against a real poller.

Voltrus Connect

Your saved sites on every device and with your team.

Save a connection profile once and have it on every Mac, iPhone and iPad you sign in on, with its register blocks. Share it with your team. Optional: Modbus Poll works fully without it. Available in Modbus Poll and BACnet Explorer first.

Sign in with your Voltrus account in the app.
Save a connection as a profile. It syncs in the background.
It appears on your other devices and with your team.

See how it works Buy yearly · $39.99

Modbus Poll on a Mac and on an iPhone, both showing the Voltrus Connect Profiles tab with the profiles MCC-1 incomer and Chiller 1 marked Synced.

Part of: Field tools · Debug one device from your laptop: protocol apps, terminal database browsers, utilities.

How MacTools Modbus Poll differs from…

Voltrus SCADA
This app is for commissioning and debugging one device from your laptop. Voltrus SCADA watches many devices around the clock, with dashboards, alarms and history on your own hardware.
Voltrus Gateway
Voltrus Gateway has no screens to click through: it is a self-hosted service that exposes Modbus, OPC UA, EtherNet/IP, S7, DNP3, BACnet/IP and MQTT to your own software over one gRPC API.

Next step

Not sure? See which one you need →

FAQ

Common questions

Does this work on Apple Silicon (M1/M2/M3/M4)? +

Yes. MacTools Modbus Poll is a native app built with Rust and Tauri. It runs natively on both Apple Silicon and Intel Macs. No Rosetta, no virtual machines needed.

Do I need Parallels or Wine to run this? +

No. This is a native app downloaded from the App Store. No Windows, no Parallels, no Wine, no Node.js, no Python. Install from the App Store and it just works.

Does it support both Modbus TCP and Modbus RTU? +

Yes. Modbus TCP connects over Ethernet/Wi-Fi by IP address and port. Modbus RTU connects over a serial port, for example a USB-to-RS485 adapter. Both protocols are supported in a single app.

Can I write to registers and coils, or just read? +

Both. You can read AND write to holding registers (FC03/FC06/FC16), coils (FC01/FC05/FC15), input registers (FC04), and discrete inputs (FC02). Values can be 16-bit signed or unsigned, 32-bit signed integer, or 32-bit and 64-bit float.

Which USB-to-RS485 adapters are supported? +

Any adapter that shows up as a serial port on your Mac (a /dev/cu.* device) can be selected in the app. Whether it shows up depends on the adapter's chip and the driver macOS has for it.

Is this a subscription? +

No. It is a one-time purchase of $19.99. No recurring fees, no in-app subscriptions, no "Pro" tier unlock. You get everything for one price.

Does it support slave/server simulation? +

Yes. The app includes both master (client) mode for polling devices and slave (server) mode for simulating Modbus devices. Load a device template like the Schneider PM5560 or SMA inverter and the slave auto-populates registers with realistic, drifting values, voltage, current, power, energy counters. Useful for testing without physical hardware.

What baud rates are supported for Modbus RTU? +

Standard baud rates from 1200 to 115200 are supported. Parity options: none, even, odd. Stop bits: 1 or 2. Data bits: 7 or 8. These cover all standard Modbus RTU configurations.

What are device templates in slave mode? +

Device templates are pre-built register maps for real industrial devices. When you load a template like the Schneider PM5560, the slave mode fills registers with the correct addresses, units, and realistic values that auto-simulate, voltage drifts, power fluctuates, energy counters increment. You can also create custom templates for any Modbus device.

Is there a PM5560 Modbus simulator? +

Yes. MacTools Modbus Poll includes a built-in Schneider PM5560 power meter simulator. The template populates all standard registers, phase voltage, current, active and reactive power, power factor, frequency, and energy totals, with realistic auto-drifting values. Connect your Modbus master and it responds like a real PM5560.

Can I simulate a Modbus power meter or solar inverter? +

Yes. Built-in templates cover the Schneider PM5560 power meter, SMA STP 60-US-10 solar inverter, ABB AZL402 water analyzer, Endress+Hauser Promag 10W flowmeter, Daniel 1000 gas flow computer, and Raritan PX3-5902V PDU. Each template uses the real device's register map with simulated live data.

Is there a Windows version? +

Yes, for Windows 10 and 11 (x64 and ARM64), as a direct download from GitHub. It is free to use with limits, and Pro is $19.99 one-time. If you bought the Mac licence on voltrus.id, the same key works on Windows, one device at a time. Purchases made in the Mac App Store have no key we can check, so they are separate. The installer is not code-signed, so Windows SmartScreen will warn you on first run. Read the Windows page.

Licensing

Need classroom, laboratory, or organization-wide licensing?

Voltrus offers Team, Academic Lab, and Enterprise Site licenses: one invoice, multi-seat usage, offline native apps. Tiers and prices are on the licensing page.

See Academic & Enterprise Options

Buy

Stop paying for Parallels.
Master and slave in one native app.

$19.99

One-time purchase, no subscription, no hidden fees

Download on theApp Store Buy Direct · $19.99 Contact Support

Stay Updated

Get notified about new features & device templates

We add new device templates, protocol features, and platform support regularly. No spam, only product updates.

Modbus Field Notes

Read the field notes

Practical Modbus references: protocol fundamentals, register addressing, and function codes with exception codes.

Guide What Is Modbus? The Protocol That Runs Industrial Automation How Modbus works, why it is still widely used after more than 40 years, and the difference between RTU, TCP, and ASCII. Reference Modbus Function Codes and Exception Codes Explained Every standard function code, the request/response frame layout, and when to use read-multiple vs write-single. Reference Modbus Addressing Explained: PLC Address vs Protocol Address Why holding register 40001 is protocol address 0, the off-by-one confusion that breaks every first Modbus project. Library Register Maps for Meters, Drives and Inverters Addresses, types, units and scale read from manufacturer manuals, with a blocks file you can import into Modbus Poll. Guide Export Your Tags to Ignition, Kepware, Node-RED and More Step-by-step guides for turning the registers you poll into a tag file for your SCADA.

From one device to the whole line

Monitoring this PLC 24/7?

Modbus Poll is built for commissioning and debugging. For round-the-clock monitoring use Voltrus OEE (hosted, live availability and downtime per machine) or Voltrus SCADA (dashboards, alarms and history on your own hardware).

Voltrus OEE → Voltrus SCADA →

Also from MacTools