lua-libmodbus

Contents

• Functions
• Context Methods

Modules

• libmodbus

Source

• lua-libmodbus.c

Module libmodbus

lua bindings to libmodbus

Info:

• Author: Karl Palsson 2016

  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Functions

Context Methods

Functions

version () line 73

Returns the runtime linked version of libmodbus as a string

Returns:

eg "3.0.6"

new_rtu (device, baud, parity, databits, stopbits) line 93

Create a Modbus/RTU context

Parameters:

• device (required)
• baud rate, defaults to 19200
• parity defaults to EVEN
• databits defaults to 8
• stopbits defaults to 1

Returns:

a modbus context ready for use

new_tcp_pi (host, service) line 154

Create a Modbus/TCP context

Parameters:

• host eg "192.168.1.100" or "modbus.example.org"
• service eg "502" or "mbap"

Returns:

a modbus context ready for use

set_s32 (num) line 189

Write a 32bit (u)int to 2x16bit registers

Parameters:

• num 32bit number

Returns:

1. reg1 upper 16bits
2. reg2 lower 16bits

set_f32 (num) line 204

Write a bit float to 2x16bit registers

Parameters:

• num floating point number

Returns:

1. reg1 upper 16bits of a 32bit float
2. reg2 lower 16bits of a 32bit float

get_s16 (1) line 222

16bit register as number to signed 16bit

Parameters:

• 1 16bit register

Returns:

signed 16bit number

get_s32 (1, 2) line 236

2x16bit registers as number to signed 32 bit

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit number

get_s32le (1, 2) line 252

2x16bit registers as number to signed 32 bit (reverse order)

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit number

get_u32 (1, 2) line 269

2x16bit registers as number to unsigned 32 bit

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit number

get_u32le (1, 2) line 285

2x16bit registers as number to unsigned 32 bit (reversed order)

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit number

get_f32 (1, 2) line 301

2x16bit registers as number to 32 bit float

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit float

get_f32le (1, 2) line 321

2x16bit registers as number to 32 bit float (Reversed order)

Parameters:

• 1 16bit register
• 2 16bit register

Returns:

32bit float

get_s64 (1, 2, 3, 4) line 343

4x16bit registers as number to signed 64 bit

Parameters:

• 1 16bit register
• 2 16bit register
• 3 16bit register
• 4 16bit register

Returns:

64bit number

get_u64 (1, 2, 3, 4) line 366

4x16bit registers as number to unsigned 64 bit

Parameters:

• 1 16bit register
• 2 16bit register
• 3 16bit register
• 4 16bit register

Returns:

64bit number

Context Methods

ctx:connect () line 424

Connect, see modbus_connect()

ctx:close () line 437

Close, see modbus_close()

ctx:set_debug (enable) line 451

Set debug

Parameters:

• enable optional bool, defaults to true

ctx:set_error_recovery (a, b) line 472

Set error recovery, see modbus_set_error_recovery FIXME get autodocs for the defined constants arguments will be or'd together

Parameters:

• a either ERROR_RECOVERY_NONE or ERROR_RECOVERY_LINK or ERROR_RECOVERY_PROTOCOL
• b as a

ctx:set_byte_timeout (seconds, microseconds) line 489

See also modbus_set_byte_timeout

Parameters:

• seconds (required)
• microseconds (optional, defaults to 0)

ctx:get_byte_timeout () line 507

Returns:

1. seconds
2. microseconds

ctx:set_response_timeout (seconds, microseconds) line 528

Parameters:

• seconds (required)
• microseconds (optional, defaults to 0)

ctx:get_response_timeout () line 546

Returns:

1. seconds
2. microseconds

ctx:get_socket () line 566

Returns:

the socket number

ctx:set_socket (sock) line 579

Parameters:

• sock integer socket number to set

ctx:set_slave (unitid) line 602

Parameters:

• unitid the unit address / slave id to use

ctx:read_input_bits (address, count) line 656

Parameters:

• address
• count

Returns:

an array of results

ctx:read_bits (address, count) line 667

Parameters:

• address
• count

Returns:

an array of results

ctx:read_input_registers (address, count) line 715

Parameters:

• address
• count

Returns:

an array of results

ctx:read_registers (address, count) line 726

Parameters:

• address
• count

Returns:

an array of results

ctx:report_slave_id () line 735

Returns:

a luastring with the raw result (lua strings can contain nulls)

ctx:write_bit (address, value) line 756

Parameters:

• address
• value either a number or a boolean

ctx:write_register (address, value) line 780

Parameters:

• address
• value

ctx:write_bits (address, value) line 797

Parameters:

• address
• value as a lua array table

ctx:write_registers (address, value) line 859

Parameters:

• address
• value as a lua array table, or a sequence of values.

Usage:

either
 ctx:write_registers(0x2000, {1,2,3})
 ctx:write_registers(0x2000, 1, 2, 3)