Communicating Via Modbus

The Sealevel SeaI/O series of digital I/O communicates serially using the Modbus protocol (http://www.modbus.org).

Enumerated below are the standard Modbus functions supported by the SeaI/O series of digital I/O. Following those are the Sealevel SeaI/O specific custom functions used for configuring and manipulating specific SeaI/O modules.

Standard Modbus Functions

(0x01) Read Coils

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(0x02) Read Discrete Inputs

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(0x03) Read Holding Registers

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(0x04) Read Input Registers

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(0x05) Write Single Coil

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(0x06) Write Single Register

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(0x0F) Write Multiple Coils

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(0x10) Write Multiple Registers

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Sealevel SeaI/O Specific Modbus Functions

(0x41) Read Programmable IO

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(0x42) Write Programmable IO

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(0x45) Get Module Configuration

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(0x46) Set Software Slave ID

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(0x47) Set Communications

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(0x64) Set A/D & D/A Configuration

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(0x65) Get A/D & D/A Configuration

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(0x66) Get Extended Module Configuration

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