Modbus ER+ Manual De Instalación página 14

Index
Description ................................................................................................................................. 14
MODBUS-RTU network structure .............................................................................................. 15
Models ER+, VR, VS, LT, DV, VRX and VSX ............................................................................... 16
Standard models (G00) and 3-position models (GF3) ............................................................................................................................. 16
BBPR models (GS6) and 3-POSITION-BBPR models (GFS) .................................................................................................................. 18
POSI (GP8) and POSI-BBPR models (GPS) ............................................................................................................................................ 20
VT+ and MT models ................................................................................................................... 22
Description
MODBUS-RTU is a serial fieldbus communication protocol to automate up to 247 electric actuators.
This protocol is non-proprietary and cheap to build. This one of the most used industrial fieldbuses because of its reliability.
Bus type
Protocol
Baud
Data bits
Parity
Stop bit
Distance
Maximum number of slave devices per line/segment
Total number of slave devices
Address range
Fonctions utilisables
03 (0x03) Read Holding Registers:
This function code is used to read the contents of a contiguous block of holding registers in a remote device.
06 (0x06) Write Single Register:
This function code is used to write a single holding register in a remote device.
16 (0x10) Write Multiple registers:
This function code is used to write a block of contiguous registers in a remote device.
23 (0x17) Read/Write Multiple registers:
This function code performs a combination of one read operation and one write operation in a single MODBUS transaction.
The write operation is performed before the read.
The read possible registers are addresses from @0 to @41 (decimal) - same as read 0x03 function
The write possible registers are addresses from @20 to @29 (decimal) – same as write 0x10 function
Broadcast
broadcast is address 0, frame is understood but NO RESPONSE of the slave. No exception generated on address 0.

RS485 transfers are immune to electromagnetic noise and unwanted signal. However, it's mandatory to use
only twisted pair with earth connected shield and within the constraints imposed by EIA-485 norm.

The distance between MODBUS cables and others must be at least 20 cm.
14
RS485
MODBUS RTU, 16 bit CRC
9600
8
none
1
1200 m
31
247 with repeater
1-247 (0=broadcast)
EN
DSBA3305 • Rév. 29/11/2021