RS485 INTERFACE (MODBUS RTU)COMMUNICATIONS GUIDE

Table 9: Master/slave packet format for performing commands

MASTER TRANSMISSION

BYTES

EXAMPLE

DESCRIPTION

 

 

 

 

SLAVE ADDRESS

1

11

message for slave

 

 

 

17

 

 

 

 

FUNCTION CODE

1

10

store multiple

 

 

 

setpoints

 

 

 

 

DATA STARTING ADDRESS

2

00 80

setpoint address

 

 

 

00 80

 

 

 

 

NUMBER OF SETPOINTS

2

00 02

2 setpoints = 4

 

 

 

bytes total

 

 

 

 

BYTE COUNT

1

04

4 bytes of data

 

 

 

 

DATA 1

2

00 05

data for address

 

 

 

00 80

 

 

 

 

DATA 2

2

00 01

data for address

 

 

 

00 81

 

 

 

 

CRC

2

7E CE

CRC error code

 

 

 

 

SLAVE RESPONSE

BYTES

EXAMPLE

DESCRIPTION

 

 

 

 

SLAVE ADDRESS

1

11

message from

 

 

 

slave 17

 

 

 

 

FUNCTION CODE

1

10

store multiple

 

 

 

setpoints

 

 

 

 

DATA STARTING ADDRESS

2

00 80

setpoint address

 

 

 

00 80

 

 

 

 

NUMBER OF SETPOINTS

2

00 02

2 setpoints

 

 

 

 

CRC

2

42 B0

CRC error code

 

 

 

 

Using the User Definable Memory Map

The MM300 contains a User Definable area in the memory map. This area allows re- mapping of the addresses of any Actual Values or Setpoints registers. The User Definable area has two sections:

1.A Register Index area (memory map addresses 020BH-0287H) that contains 125 Actual Values or Setpoints register addresses.

2.A Register area (memory map addresses 020BH-0287H) that contains the data at the addresses in the Register Index.

Register data that is separated in the rest of the memory map may be re-mapped to adjacent register addresses in the User Definable Registers area. This is accomplished by writing to register addresses in the User Definable Register Index area. This allows for improved throughput of data and can eliminate the need for multiple read command sequences. The User Definable Register Index is stored as a setpoint and therefore it is “remembered” even when the power is removed.

For example, if the values of MOTOR LOAD (register address 014FH; modbus address 30336) and DRIVE STATUS (register address 0135H; modbus address 30310) are required to be read from a MM300, their addresses may be re-mapped as follows:

1.Write 30336 to address 020BH (40524) (User Definable Register Index 0000) using function code 06 or 16.

2.Write 30310 to address 020CH (40525) (User Definable Register Index 0001) using function code 06 or 16.

The MM300PC software can be used to write these locations to the User Definable Register

Index using the Setpoints > Modbus Memory Map > User Map screen.

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MM300 MOTOR MANAGEMENT SYSTEM – COMMUNICATIONS GUIDE

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GE MM300 manual Using the User Definable Memory Map, Master/slave packet format for performing commands, CRC 7E CE
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MM300 specifications

The GE MM300 is a robust and versatile controller designed primarily for industrial automation applications. Built to tackle the demands of modern manufacturing environments, this controller offers a range of features that contribute to its popularity among engineers and operators.

One of the standout features of the GE MM300 is its scalability. The device can be easily configured to meet the needs of both small and large systems. Its modular architecture allows users to add or remove components based on the specific requirements of their applications, facilitating a more tailored approach to automation.

The MM300 supports various communication protocols, including Ethernet/IP, Modbus TCP, and more, ensuring seamless integration with a variety of devices and systems. This feature significantly enhances interoperability, allowing users to connect the controller to existing infrastructure without extensive reconfiguration.

In terms of processing power, the MM300 is equipped with a high-performance processor that can handle complex tasks with ease. With advanced data handling capabilities, it supports real-time data processing, enabling faster decision-making and improving overall operational efficiency. This capability is particularly beneficial for applications requiring precise control and monitoring.

Moreover, the GE MM300 boasts a user-friendly interface, featuring an intuitive programming environment that simplifies the development of control applications. This includes an integrated development environment (IDE) and support for popular programming languages, making it accessible for both seasoned programmers and those new to automation technologies.

The device is designed to operate in challenging industrial conditions, featuring a rugged construction that ensures durability and longevity. Its ability to withstand extreme temperatures, vibrations, and other environmental stressors enhances its reliability in demanding applications, which is crucial for minimizing downtime in production processes.

Security is another critical aspect of the GE MM300. The controller incorporates advanced security features to protect against unauthorized access and cyber threats, helping organizations ensure the integrity of their operations.

In summary, the GE MM300 stands out due to its scalability, versatile communication options, high processing capabilities, user-friendly programming environment, rugged design, and security features. These characteristics make it a reliable choice for industries seeking to enhance their automation processes and improve overall efficiency. Whether for small-scale or large-scale applications, the MM300 provides a comprehensive solution to meet the evolving needs of modern manufacturing.
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