Trip Unit Communication Network

Wiring System ULP

The wiring system is designed for low-voltage power switchboards. Installation does not require special tools or training. The prefabricated wiring provides both data transmission (Modbus protocol) and 24 Vdc power distribution for the communications modules on the MicroLogic trip units.


A. FDM128 display for 8 LV devices B. IFE Ethernet interface for LV circuit breaker and gateway C. IFM Modbus-SL interface for LV circuit breaker D. FDM121 display for LV circuit breaker E. IO input/output interface module for	F. PowerPacT H-, J-, or L-frame circuit breaker G. ULP line terminator H. ULP cable I. Circuit breaker ULP cord J. NSX cord

Four Functional Levels

A: MicroLogic trip unit with ammeter

P: MicroLogic trip unit “Power”

H: MicroLogic trip unit “Harmonics”

The MasterPacT can be integrated into Ethernet and Modbus communication environment.

There are four possible functional levels that can be combined.

Functional Level	Switch	Circuit Breaker
Status Indications
ON/OFF (O/F) \	X	A	P	H
Spring charged	X	A	P	H
Ready to close	X	A	P	H
Fault-trip SDE	X	A	P	H
Connected / disconnected / test position CE/CD/CT (CCM only)	—	A	P	H
Controls
MX1 shunt trip	X	A	P	H
XF shunt close	X	A	P	H
Measurements
Instantaneous measurement information	—	A	P	H
Averaged measurement information	—	—	—	H
Maximum / minimum Ammeter	—	A	P	H
Energy metering	—	—	P	H
Demand for current and power	—	—	P	H
Power quality	—	—	—	H
Operating Assistance
Protection and alarm settings	—	—	P	H
Histories	—	—	P	H
Time stamped event tables	—	—	P	H
Maintenance indicators	—	A	P	H

Modbus Principle

Modbus Principle

The Modbus RS 485 (RTU protocol) system is an open bus on which communicating Modbus devices (MasterPacT NW with Modbus COM, Power Meter PM700, PM800, PowerPacT P/R frame, etc.) are installed. All types of PLCs and microcomputers may be connected to the bus.

Addresses

The Modbus communication parameters (address, baud rate, parity) are entered using the keypad on the MicroLogic A, P, or H trip unit. For a switch, it is necessary to use the Electrical Asset Manager or RSU (Remote Setting Utility) MicroLogic utility.

Number of Devices

The maximum number of devices that may be connected to the Modbus bus depends on the type of device (ComPacT circuit breaker with Modbus COM, PM700, PM800, MasterPacT circuit breaker, etc.), the baud rate (19200 is recommended), the volume of data exchanged and the desired response time. The RS 485 physical layer offers up to thirty-two connection points on the bus (one master, thirty-one slaves).

Length of Bus

The maximum recommended length for the Modbus bus is 3940 feet (1200 meters).

Bus Power Source

A 24 Vdc power supply is required (less than 20% ripple, insulation class II).

Ethernet Principle

Ethernet is a data link and physical layer protocol defined by IEEE 802 10 and 100 Mbps specifications that connects computer or other Ethernet devices. Ethernet is an asynchronous Carrier Sense Multiple Access with Collision detection (referred as CSMA/CD) protocol. Carrier Sense means that the hosts can detect whether the medium (coaxial cable) is idle or busy.

Multiple Access means that multiple hosts can be connected to the common medium. Collision Detection means a host detects whether its transmission has collided with the transmission of another host (or hosts).

IFE Ethernet interface can be connected to a PC or a laptop over Ethernet. The maximum length of Ethernet cable is 325 feet (100 meters). IFE Ethernet interface + gateway provides a Modbus TCP/IP gateway over Ethernet to enable Modbus TCP communication from a Modbus TCP master to any Modbus slave devices connected to it. The maximum active Modbus TCP client connection is twelve.

IFE Ethernet interface has an embedded web server (web page).