An industrial communications protocol used for connecting industrial electronic devices.
Features
About ModbusWith Cs/Modbus, you can use either ASCII frames or RTU frames, or both at the same time if you have multiple serial interfaces. Cs/Modbus module supports any number of communications channels. Modbus-S is a Modbus Slave (server) software component enabling an embedded system to communicate to a Modbus Master (client). Modbus-M is a Modbus Master (client) component that enables communication to a Modbus Slave. Cs/Modbus module enables a developer to read or write integer, floating-point (assuming Daniels extensions), and discrete values from and to the target system.
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Key FeaturesThe features of Cs/Modbus module include:
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Specifications
Key Specifications
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• Unlimited number of ‘channels’ (limited only by the number of serial interfaces) |
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• ASCII or RTU mode selectable on a per-channel basis |
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• Floating-point support through “Daniel’s Extensions” |
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• Modbus Slave or Master possible on the same product |
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• Adjustable baud rate on a per channel-basis |
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• Easily assign application variables to Modbus registers, coils, and discrete inputs |
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• Works with any processor (8-, 16-, 32-, 64-bit, or DSP) |
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• Works with or without an RTOS kernel |
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• Easily configurable |
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• ANSI C source code provided |
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• Scalable from 6K to 15K bytes of code space |
Function Codes
Supported Modbus function codes:
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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 |
