User manual
URDR0001 - User manual - 29
8 Serial Communication
URDR0001, equipped with RS485, can receive and broadcast data via serial
communication using MODBUS RTU protocol. The device can only be congured
as a Slave. This function enables the control of multiple controllers connected to
a supervisory system (SCADA). Each controller responds to a master query only if
the query contains the same address as that in the parameter
SL.Ad .
The permitted addresses range from 1 to 254 and there must not be controllers
with the same address on the same line. Address 255 can be used by the master
to communicate with all the connected equipment (broadcast mode), while with
0 all the devices receive the command, but no response is expected.
URDR can introduce a delay (in milliseconds) in the response to the master
request. This delay must be set on parameter 72
se. d e.
Each parameter change
is saved by the controller on EEPROM memory (100000 writing cycles), while the
setpoints are saved with a delay of ten seconds after the last change.
NB: changes made to Words that are dierent from those reported in the fol-
lowing table can lead to malfunction.
Modbus RTU protocol features
Baud-rate
Selection on parameter 70
bd . rt.
:
4.8 k
4.800 bit/Sec.
28.8k
28.800 bit/Sec.
9.6 k
9.600 bit/Sec.
38.4 k
38.400 bit/Sec.
19.2k
19.200 bit/Sec.
57.6k
57.600 bit/Sec.
Format 8, N, 1 (8 bit, no parity, 1 stop)
Supported
functions
WORD READING (max 20 word) (0x03, 0x04)
SINGLE WORD WRITING (0x06)
MULTIPLE WORDS WRITING (max 20 word) (0x10)
Looking at the table here below it is possible to nd all available addresses and
functions:
RO Read Only R/W Read / Write WO Write Only