Support

Getting help with Modbus Poll

Frequently Asked Questions

I can't connect to my Modbus TCP device.

Check that the device IP address and port are correct (default Modbus TCP port is 502). Ensure your Mac and the device are on the same network. If using a VPN or firewall, verify that port 502 is not blocked. Try pinging the device IP from Terminal: ping 192.168.1.100

My USB-to-RS485 adapter isn't detected.

Open the app and go to Master mode → RTU. Click the port dropdown to see available serial ports. If your adapter doesn't appear, check that it's plugged in and the macOS driver is installed. Supported chips: FTDI FT232, CH340/CH341, CP2102, PL2303. On Apple Silicon Macs, FTDI and CH340 adapters work without additional drivers.

My license key doesn't work.

Make sure you enter the full key including dashes (format: XXXX-XXXX-XXXX-XXXX). Check that you have an internet connection during first activation: the app needs to validate the key once. After activation, the app works offline. If you still have trouble, contact support below.

How do I read holding registers?

In Master mode, connect to your device (TCP or RTU). Then add a read block: set the start address, quantity, and type (UINT16, INT16, FLOAT32, etc.). Click "Read" to poll once, or set a poll interval to read continuously.

How do I simulate a Modbus device?

Switch to Slave mode. Start a TCP server (default port 5020) or RTU server. Load a device template like PM5560 or SMA inverter: registers auto-populate with realistic values. Connect any Modbus master to your Mac's IP and the slave port.

I bought from the Mac App Store. Do I need a license key?

No. The Mac App Store version is automatically licensed through your Apple ID. No license key needed. The paywall only appears in the direct-download (DMG) version.

I bought via Polar.sh but want to switch to the Mac App Store.

Purchases through Polar.sh and the Mac App Store are separate. We cannot transfer purchases between platforms. Both versions are identical in features.

The app crashes or freezes.

Make sure you're running macOS 13 (Ventura) or later. If the app freezes during a Modbus operation, try disconnecting and reconnecting. If the issue persists, contact support with your macOS version, the app version, and what you were doing when it happened.

Contact Support

Email

For bug reports, feature requests, license issues, or general questions.

[email protected]

Please include:

  • Modbus Poll version (find in app → Info)
  • macOS version
  • Mac model (Intel or Apple Silicon)
  • Steps to reproduce the issue

Response Time

We aim to respond within 24 hours on business days. Complex issues may take longer. License-related questions are typically answered within a few hours.

Refund Policy

Mac App Store purchases: Refunds are handled by Apple through your App Store account settings.

Polar.sh purchases: Contact us at the email above within 30 days of purchase for a full refund. No questions asked.