GE P485 instruction manual Document conventions, Input and output definition

INTRODUCTION

Document conventions

DESCRIPTION The following conventions are used throughout this document:

•Numbered lists provide sequential steps.

•Bulleted lists provide information, not procedural steps.

•The term ‘user’ refers to the person or persons responsible for installing the P485 Modbus to Profibus Converter in a network.

•Hexadecimal values are written in the format 0xNNNN, where NNNN is the hexadecimal value.

•Decimal values are represented as NNNN, where NNNN is the decimal value.

•As in all communication systems, the terms “input” and “output” can be ambiguous, since their meaning depends on which end of the link is being referenced. The convention in this document is that “input” and “output” are always being referenced to the master/scanner end of the link (see illustration below).

•The term “sub-network” is interchangeably used for “Modbus network”.

Profibus master

IN OUT Profibus network

Slave

GE Multilin

P485 Converter

Slave

IN OUT

Modbus network

Figure 1-1: Input and output definition

GLOSSARY The following terminology is used in the P485 manual:

•Broadcaster: A protocol specific node in the sub-network scan that holds transactions destined for all nodes.

•Command: A protocol specific transaction.

•Fieldbus: The network to which the converter is connected (Profibus for P485).

•Frame: A higher level series of bytes forming a complete telegram on the sub-network (Modbus).

•Monitor: A tool for debugging the P485 and network connections.

•Node: A device in the scan list that defines the communication with a slave (GE relay) on the Modbus sub-network.

•Scan list: List of configured slaves with transactions on the sub-network.

•Sub-network: Modbus network that logically is located on a subsidiary level with respect to the fieldbus and to which the P485 acts as a gateway.

•Transaction: A generic building block that is used in the sub-network scan list and defines the data that is sent out the sub-network.

1–2 P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE