Modbus Slave Operation Via Serial Interface - JUMO mTRON T Manual

4.2

Modbus slave operation via serial interface

If the central processing unit has been configured as a slave, it responds to Modbus requests
from the master in the network. The master controls the data exchange and the slaves only
have a response function. They are identified by means of their device address.
The master is usually a PC with a setup or visualization program or another Modbus-capable
device. The master can request all device variables according to the Modbus address tables of
this slave.
 Chapter 7 "Modbus address tables", page 77
During slave operation, the central processing unit can operate as several virtual devices with
several device addresses.
 Chapter 5.2 "Networking with Modbus/TCP", page 59
All modules connected to the central processing unit can be addressed with their respective
device addresses that were assigned in the setup program under H
This makes it possible to always use the same Modbus addresses for the same type of mod-
ules.
SystemIO
data
Config.
parameters
...
4 Serial transmission modes
Interface parameters
+ Modem parameters
(if applicable)
+ E-mail parameters
(if applicable)
Driver
(base unit)
RS232/
RS485
Modem
(if applicable)
Alarm message
ARDWARE ARRANGEMENT
.
51