4.11 Modbus Functions

Overview

The Modbus module encapsulates the robot’s capabilities when acting as a Modbus master: slave management, register read/write, and serial-port parameter configuration, facilitating linkage with PLCs, I/O expansion modules, and other Modbus devices.

Core Features

• Support for obtaining Modbus slave instances by channel and slave ID
• Support for reading and writing Modbus coil registers from slaves
• Support for reading and writing Modbus holding registers from slaves
• Support for reading Modbus discrete input registers from slaves
• Support for reading Modbus input registers from slaves
• Support for setting and querying serial communication parameters

Use Cases

• Data exchange with PLC devices
• Control of I/O expansion modules
• Implementation of linkage between robots and other Modbus devices
• Configuration and management of Modbus serial communication parameters

Notes

Modbus functions conflict with the bus configuration on the robot software and cannot be used simultaneously.

4.11.1 Get Modbus Slave Instance

Method Name	modbus.get_slave( channel : ModbusChannel, slave_id : int, master_id : int = 0) -> 'Modbus.Slave'
Description	Get a Modbus slave instance for the specified channel and slave ID.
Request Parameters	channel : ModbusChannel Modbus channel slave_id : int Slave ID master_id : int Master ID (default 0)
Return Value	Modbus.Slave: Modbus slave instance
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.2 Read Modbus Coil Registers from a Slave

Method Name	slave.read_coils( address : int, number : int ) -> tuple[list[int], StatusCodeEnum]
Description	Read Modbus coil registers from a slave.
Request Parameters	address : int Register address number : int Register count (max 120)
Return Value	list[int]: Register values StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.3 Write to Modbus Coil Registers of a Slave

Method Name	slave.write_coils( address : int, value : list[int]) -> StatusCodeEnum
Description	Write to Modbus coil registers of a slave.
Request Parameters	address : int Register address value : list[int] Register values
Return Value	StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.4 Read Modbus Holding Registers from a Slave

Method Name	slave.read_holding_regs( address : int, number : int ) -> tuple[list[int], StatusCodeEnum]
Description	Read Modbus holding registers from a slave.
Request Parameters	address : int Register address number : int Register count (max 120)
Return Value	list[int]: Register values StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.5 Write to Modbus Holding Registers of a Slave

Method Name	slave.write_holding_regs( address : int, value : list[int]) -> StatusCodeEnum
Description	Write to Modbus holding registers of a slave.
Request Parameters	address : int Register address value : list[int] Register values
Return Value	StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.6 Read Modbus Discrete Input Registers from a Slave

Method Name	slave.read_discrete_inputs( address : int, number : int ) -> tuple[list[int], StatusCodeEnum]
Description	Read Modbus discrete input registers from a slave.
Request Parameters	address : int Register address number : int Register count (max 120)
Return Value	list[int]: Register values StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.7 Read Modbus Input Registers from a Slave

Method Name	slave.read_input_regs( address : int, number : int ) -> tuple[list[int], StatusCodeEnum]
Description	Read Modbus input registers from a slave.
Request Parameters	address : int Register address number : int Register count (max 120)
Return Value	list[int]: Register values StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

Example Code

modbus.py

#!python
"""
Copyright © 2016 Agilebot Robotics Ltd. All rights reserved.
Instruction: modbus使用示例 / Example of modbus usage
"""

from Agilebot import Arm, ModbusChannel, SerialParams, StatusCodeEnum

# [ZH] 初始化Arm类
# [EN] Initialize the robot
arm = Arm()
# [ZH] 连接控制器
# [EN] Connect to the robot
ret = arm.connect("10.27.1.254")
if ret == StatusCodeEnum.OK:
    print("机器人连接成功 / Robot connected successfully")
else:
    print(f"机器人连接失败，错误代码 / Robot connection failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

# [ZH] 设置modbus参数
# [EN] Set Modbus parameters
params = SerialParams(channel=ModbusChannel.CONTROLLER_TCP_TO_485, ip="10.27.1.80", port=502)
id, ret_code = arm.modbus.set_parameter(params)
if ret_code == StatusCodeEnum.OK:
    print("设置Modbus参数成功 / Set Modbus parameters successfully")
else:
    print(f"设置Modbus参数失败，错误代码 / Set Modbus parameters failed, error code: {ret_code.errmsg}")
    arm.disconnect()
    exit(1)

# [ZH] 创建从站
# [EN] Create a slave
slave = arm.modbus.get_slave(ModbusChannel.CONTROLLER_TCP_TO_485, 1, 1)

# [ZH] 写入
# [EN] Write to registers
value = [1, 2, 3, 4]
ret = slave.write_coils(0, value)
if ret == StatusCodeEnum.OK:
    print("写入线圈成功 / Write coils successfully")
else:
    print(f"写入线圈失败，错误代码 / Write coils failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

ret = slave.write_holding_regs(0, value)
if ret == StatusCodeEnum.OK:
    print("写入保持寄存器成功 / Write holding registers successfully")
else:
    print(f"写入保持寄存器失败，错误代码 / Write holding registers failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

# [ZH] 读取
# [EN] Read registers
res, ret = slave.read_coils(0, 4)
if ret == StatusCodeEnum.OK:
    print("读取线圈成功 / Read coils successfully")
    print(f"读取的线圈值 / Read coil values：{res}")
else:
    print(f"读取线圈失败，错误代码 / Read coils failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

res, ret = slave.read_holding_regs(0, 4)
if ret == StatusCodeEnum.OK:
    print("读取保持寄存器成功 / Read holding registers successfully")
    print(f"读取的寄存器值 / Read register values：{res}")
else:
    print(f"读取保持寄存器失败，错误代码 / Read holding registers failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

res, ret = slave.read_input_regs(0, 4)
if ret == StatusCodeEnum.OK:
    print("读取输入寄存器成功 / Read input registers successfully")
    print(f"读取的输入寄存器值 / Read input register values：{res}")
else:
    print(f"读取输入寄存器失败，错误代码 / Read input registers failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

res, ret = slave.read_discrete_inputs(0, 4)
if ret == StatusCodeEnum.OK:
    print("读取离散输入成功 / Read discrete inputs successfully")
    print(f"读取的离散输入值 / Read discrete input values：{res}")
else:
    print(f"读取离散输入失败，错误代码 / Read discrete inputs failed, error code: {ret.errmsg}")
    arm.disconnect()
    exit(1)

# [ZH] 结束后断开机器人连接
# [EN] Disconnect from the robot
arm.disconnect()
print("机器人断开连接成功 / Robot disconnected successfully")

4.11.8 Set Serial Communication Parameters

Method Name	modbus.set_parameter( param : SerialParams) -> tuple[int, StatusCodeEnum]
Description	Set serial communication parameters.
Request Parameters	param : SerialParams Serial communication parameters
Return Value	int: Channel ID StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

4.11.9 Get Serial Communication Parameters

Method Name	modbus.get_parameter( channel : ModbusChannel, master_id : int = 1) -> tuple[SerialParams, StatusCodeEnum]
Description	Get serial communication parameters.
Request Parameters	channel : ModbusChannel Modbus channel master_id : int Master ID (default 1)
Return Value	SerialParams: Serial communication parameters StatusCodeEnum: Result of the function execution
Compatible robot software version	Collaborative (Copper): v7.6.0.0+ Industrial (Bronze): v7.6.0.0+

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