SCHNEIDER PowerPact ™ H. Modbus Communication User Guide for J and L-type Circuit Breakers

Communication interface: Dual RJ45 communication ports, supporting daisy chain connection, but embedded switches do not support ring topology (without loopback protection).

IP configuration: Default DHCP mode, press the reset button for 1-5 seconds to restore the default IP configuration.

Power requirements: A 24Vdc power supply is required, and it is recommended to use a UL labeled and approved limited voltage/current level 2 power supply (maximum 3A), with only copper wires used for wiring; The IFM interface stacked on the IFE server is powered by the IFE server and does not require separate power supply.

Padlock function: Consistent with the IFM interface, the arrow points to open the padlock to enable remote control commands, and close it to disable it. Only the "Set Absolute Time" command is not restricted.

Features: Supports device configuration file network services (discovering IFE interfaces within the local area network), ULP compatibility (adapting to installation and positioning in distribution panels), embedded settings/monitoring/control web pages, server functionality for Modbus SL connected devices (limited to LV434002), email alarm notifications.

Hardware Description and Installation

Hardware composition: Includes dual RJ45 communication ports, 24Vdc power terminal block, QR code (product information), Ethernet communication LED, module status LED, network status LED, sealable transparent cover, reset button, ULP status LED, test button, padlock, Modbus traffic status LED (IFE server only), device name label, two RJ45 ULP ports, grounding connection.

Installation method: Installed on a DIN rail, LV434002 IFE server can be connected to multiple IFM interfaces through stacked accessories without additional wiring.

Indicator light status description

Ethernet communication LED: Dual color LED indicates the status of ETH1 and ETH2 ports, off indicates no power or no link; The constant yellow light indicates the establishment of a 10 Mbps link but no activity, while the flashing yellow light indicates the 10 Mbps active state; A constant green light indicates that a 100 Mbps link has been established but there is no activity, while a flashing green light indicates a 100 Mbps active state.

Module status LED: The dual color LED indicates the status of the IFE interface, and off indicates that it is not powered on; A constant green light indicates normal operation; Green light flashing (250ms on/off) indicates that the hidden control webpage is available; Green light flashing (500ms on/off) indicates firmware damage; Red light flashing (500ms on/off) is in degraded mode; If the red light is constantly on, it means it has stopped running; Green/red flashing alternately (switching for 1 second) indicates firmware update in progress; The rapid alternating flashing of green/red light (250ms switching) indicates self checking.

Network status LED: Dual color LED indicates network status, off indicates no power or no IP address; A green light that stays on is a valid IP address; A constant red light indicates a duplicate IP address; Alternating flashing of green/red light (250ms switching) indicates self-test; An amber constant light indicates an IP configuration error.

Modbus Traffic Status LED: Only available on IFE servers. A yellow LED indicates that data is being transmitted or received through the Modbus serial line network. If it is turned off, there will be no data transmission.

Deep Analysis of Modbus Protocol

(1) Basic Principles of Communication

Master slave mode: Adopting a one master multiple slave mode, one master device (monitor/PLC) can connect up to 31 slave devices (circuit breakers), and only one master device can connect to the network at a time.

Communication process: Only the master device can initiate communication and send requests. It can access a single slave device through a separate address or broadcast access to all slave devices using address 0; The slave device can only respond to requests from the master device and cannot initiate communication or communicate with other slave devices.

Response time: The typical response time is less than 10ms, with a maximum value of about 700ms. It is recommended to have an interval of ≥ 1 second between two Modbus requests to avoid communication conflicts.

Data type: Supports register (16 bit) data type, does not support single bit type; The relationship between register number and address is "address=register number -1", for example, the address of register number 12000 is 0x2EDF (11999).

Frame structure: Each Modbus frame has a maximum of 256 bytes and contains 4 fields - slave device number (1 byte, 0 for broadcast, 1-247 for independent addresses), function code (1-2 bytes), data (n registers, n maximum of 52, with MasterPact MicroLogic E trip unit), CRC16 checksum (2 bytes, detecting transmission errors).

(2) Core functional code

Function code, sub function code name, usage restriction explanation

0x03- Read hold register Read output/Internal registers (such as measurement values, device status) Read up to 52 registers

0x04- Read Input Register Read Input Register (such as sensor data) Read up to 52 registers