A P P L I C A T I O N N O T E
E 9 T U S A G E I N I N D U S T R I A L F I E L D
A P N t 0 2 6 E 9 TU I F
E N R e v .1 . 1
T U R B O s . r .l .
D u s t F i l t e r C o m p o n e n t s
V i a C e n t r o I n d u s t r i a l e E u r o p e o , 3 3
–
T u r a t e ( C O ) I t a l y
T e l + + 3 9 0 3 6 2 5 7 4 0 2 4 F a x + + 3 9 0 3 6 2 5 7 4 0 9 2
1 0
RS-485 Modbus RTU
The RS-485 Modbus RTU is a serial communication standard for industrial controllers that uses a differential signal
over twisted pair wires to drive digital information at long distances supporting local networks and multidrop
communication.
The RS-485 is used as the physical layer underlying many automation protocols including Modbus.
The Modbus is a serial communication protocol for use with PLC’s and supervisory (RTU, SCADA) systems.
Each device on the network using Modbus is provided of a unique and configurable address.
The E9T control unit supports the RTU format, that makes use of a compact binary representation of the data.
The Modbus physical layer
WARNING
The length and quality of the RS-485 line affect the
quality of the signal. Though the theoretical maximum
length of a RS-485 Bus is 1200 meters for data rates
between 100Baud and 100KBaud.
Requirements of wiring in order to obtain good signal quality:
1)
Section min 2 +1 x 0,32mm2(a twisted pair and a single
pole
2)
Shielded
3)
Twisted pair cables
4)
Resistant to UV rays (for outdoor installation only)
5)
CAT.5 cable
