Telurometros

ABB

MSOC AN-64A-00

Application Note

Substation Automation and Protection Division

MSOC Communication Commonality with DPU/TPU/GPU 2000R Protective Relays
Introduction
There seems to be some confusion with ABB's implementation of Modbus on the 2000R and MSOC product lines. This Application Note is intended to dispel the ambiguities. The DPU/TPU/GPU 2000R and MSOC devices allowconnectivity as a slave device (receiving commands and responding to a host request) on the Modbus Network. The DPU/TPU/GPU protective devices allow for both emulations of Modbus, namely RTU and ASCII. The MSOC allows for one single emulation of Modbus, namely ASCII. The DPU 2000R and the MSOC can communicate on the same network if both devices are configured as MODBUS ASCII slave nodes. Thisapplication note illustrates the step by step method of configuring the MSOC and DPU/TPU/GPU 2000R units attached to the same network.

RS 485 Device Connectivity
An RS 232 physical interface offers point to point connectivity. If multiple devices must be interconnected (multi-drop architecture), the physical interface must be changed from RS 232 to a physical interface configuration which allows for amulti-drop architecture. Both the MSOC and DPU/TPU/DPU 2000R products have isolated RS 485 ports (MSOC through terminals 8,9, and 10. and the DPU/TPU/GPU products through the AUX com port as a standard via terminals 55,56 and 57). Communications in a multi-dropped architecture can occur via an RS 485 network with DPU/TPU/GPU 2000R's and MSOC's attached within the wiring constraints of the RS 485ANSI standards. Figure 1 illustrates the RS 485 connectivity to a host device connected via a RS 485 network. Figure 2 illustrates the RS 232 cable connecting the PC with the RS 485 physical interface converter.
Use Figure 2 Cable

Unicom Physical Interface Converter Switch Settings:
- DTE - RS232-RS485 - 9600 Baud - HD TX RX TX + RX + GND

Terminal 8 - RS485 Common Terminal 9 - RS 485Negative Terminal 10-RS 485 Positive Install J6, J7 and J8- Termination resistor, Pullup resistor, and Pulldown resistor in the MSOC.

Install 120 ohm resistor between + and - terminals for device termination. Install J6

1 2 3 4 5 6 7 8 9 10

55 56 57 58 59 60 61 ----RS 485 Isolated Port
3

Shield Isolated

GND

11 12 13 14 15 16 17 18 19 20

DPU/TPU/GPU 2000R Unit Address 16

21 22 2324 25 26 27 28

MSOC Unit Address 1

Shield is Frame Grounded at one point

Figure 1 - RS 485 Architecture for example system.

MSOC Communication Commonality with DPU/TPU/GPU 2000R Protective Relays AN-64A-00

Unicom Converter
2Receive Data 3Transmit Data 5Ground

PC
2 Transmit Data 3 Receive Data 5 Ground 1 Data Carrier Detect 6 Data Set Ready 4 Data Terminal Ready 7 Request ToSend 8 Clear To Send 9 Ring Indicator

DTE 9 pin D shell Male Connector

-No connection

DTE 9 pin D shell Female Connector

Figure 2 - Unicom RS 485 Converter to PC Cable 9 to 9 Pin-out

Device Configuration Via The Front Panel Interface
To further allow communications between the devices, a common port set-up must be configured, namely, baud rate, stop bits, data bits, and parity. TheMSOC and the DPU/TPU/GPU 2000R share the following configurations: Shared baud rates are: • 1200 • 2400 • 4800 • 9600 • 19200 Shared recommended frame configurations are: • Odd parity, 7 Data Bits, One stop Bit. • Even parity, 7 Data Bits, One stop Bit. With each device on the network configured in one shared and common configuration (as referenced above), communications between a Host device andMSOC's and DPU/TPU/GPU 2000R's shall occur. The MSOC and DPU/TPU/GPU product families are designed to communicate on a common Modbus network. This example shall illustrate a network configuration with two devices attached communicating at 9600 baud 7 data bits, one stop bit, and odd parity. This is only one of several combinations which may be used in a communication configuration.

MSOC...