µC/Modbus
The Modbus protocol consists of the reception and transmission of data, in predefined packets, referred to as “frames.” The Modbus protocol operates with two types of frames: an ASCII frame, and a Remote Terminal Unit (RTU) frame. The ASCII frame is a frame based on ASCII hexadecimal characters, while the RTU frame is strictly a binary implementation. ASCII mode is easier to implement and debug but offers roughly half the data transfer speed of RTU mode. With μC/Modbus, you can use either mode.
μC/Modbus supports any number of communications channels. The ASCII or RTU mode of operation is selectable on a per ‘channel’ basis. μC/Modbus-S is a Modbus Slave (server) software component enabling an embedded system to communicate to a Modbus Master (client). μC/Modbus-M is a Modbus Master (client) component that enables communication to a Modbus Slave.
μC/Modbus enables a developer to read or write integer, floating-point (assuming Daniels extensions) and discrete values from and to the target system.
Applications
µC/Modbus is used in a wide variety of industries:
- Industrial controls
- Process control
- Food processing
- Smart sensors
- A wide-range of embedded applications
Features
µC/Modbus include the following features:
- Enables multiple serial interfaces on a single target system
- Allow for multiple RS-232C or RS-485 ports on the same target, limited only by the number of serial ports available. The baud rate depends on the processor used.
- Supports both Modbus ASCII and RTU on an individual channel basis.
- Assign nearly any application variable to any Modbus holding register (up to 65536), input register (up to 65536), coil (up to 65536) or input status (up to 65536).
- Complete, clean ANSC source code included
- Scalable from 6 to 15 kBytes. Compile only the function codes necessary for the target.
Supported Modbus function codes
| Function Code | Description |
|---|---|
| 1 | Coil Read |
| 2 | Discrete Input Read |
| 3 | Holding Register Read |
| 4 | Input Register Read |
| 5 | Write Single Coil |
| 6 | Write Single Holding Register |
| 8 | Diagnostic Loopback |
| 15 | Write Multiple Coils |
| 16 | Write Multiple Holding Registers |
| 20 | File Read |
| 21 | File Write |
Monitoring
Use μC/Probe to visualize all μC/Modbus-based applications allowing a design engineer to monitor and change values in a product at run-time. μC/Probe interfaces to any embedded target whether or not it has a real-time kernel, and works with any 8-, 16-, 32-, 64-bit CPU or DSP. μC/Probe saves valuable time throughout product design, and can also serve as a product’s user interface.
For pricing, delivery, and ordering information, contact Micrium today.