Document conventions, Description, Glossary – GE P485 User Manual
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P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE
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”.
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.
Profibus
master
Slave
GE Multilin
P485 Converter
Slave
Modbus
network
Profibus network
OUT
IN
OUT
IN