EVCO EVD120 - Manual (Page 30)

Evco S.r.l.
ModBUS PRJ314AA06 v1.02 12 th December 2006 page 2 of 8
1 INTRODUCTION
This document describes the resources of the device that can be accessed via the serial port. The protocol is
MODBUS RTU/JBUS.
2 LIST OF DEVICES
This document applys to :
Device Name/Family Notes
EVD120M7
3 ADDRESSING CONVENTIONS
Please note that according to MODBUS specs:
the first register is called register 1
register x must be read ad address x-1
According to JBUS:
the first register is called register 0
register x must be read ad address x
The JBUS convention (zero based) has been used in this document, addresses are shown in hexadecimal
with the leading symbol $.
4 IMPLEMENTED MODBUS FUNCTION CODES
Command Function Code Notes
READ HOLDING REGISTERS $03 Maximum 30 registers at once
WRITE SINGLE REGISTER $06
WRITE MULTIPLE HR $10 Maximum 30 registers at once
READ AND WRITE MULTIPLE HR $17 Maximum 30 registers at once