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.

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.

How do I restore my purchase on a new Mac?

Purchases are tied to your Apple ID. Sign in to the App Store with the same Apple ID and install the app again. In-app purchases can be restored from the app's About window.

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, purchase questions, or anything else.

[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 reply within two business days. A full fix for a complex issue may take longer.

Refund Policy

Purchases are made through the App Store. Refunds are handled by Apple: request one at reportaproblem.apple.com.