What is Modbus Monitor?
It is a Android app that talks Modbus protocol using several types of interface. This app polls the Modbus Speaking devices for the data right from your mobile devices. This app is also able to turn itself into "Server" so any Modbus Master on the network can poll your mobile devices. This app also accesses your devices' sensor data. This app is also able to use your PC USB Serial Port dongles to talk to your devices (PLC, pressure sensor, temperature controllers, etc) that is not connected to Ehternet or Wi-Fi. So, the Modbus Monitor is three apps in one: Modbus TCP/UDP Master, Modbus TCP (only) Server, and Modbus RTU/ASCII Master.
User's Guide or Help? Click Here
Following video shows the top features of Modbus Monitor. This video shows how to use the Modbus TCP master, Modbus TCP Server, and Modbus TCP Sensor Server.
Check out this video on using the USB-OTG interface with Modbus Monitor App. The USB serial ports made by Prolific and FTDI are supported but only with specific chipset. See Android Play store description for details.
Brief Introduction of Sensor Server
When Modbus TCP Server feature is used, you can specify the the monitor point to get the data from internal server and update it regularly. This same data will be available on the Modbus TCP Server Network. The sample is shown in the YouTube video.
Modbus Master / Client Features
Modbus Slave (Server) Features