User manual - ATR171 23
9 Serial communication (only for ATR171-23ABC-T)
To enable serial input set the dip switchs as indicated in the figure:
In this configuration mode, parameters
and functioning related to double
analogue input are not available.
9.1 Modbus RTU
ATR171-23ABC-T is provided with RS485 and can receive/broadcast data via
MODBUS-RTU protocol. Device can be configured only as Slave. This function allows
to control multiple controllers connected to a supervisory system (SCADA).
Each instrument will answer to a Master query only if contains same address as on
parameter 84
SL. a d .
. Allowed addresses are from 1 to 254 and there should not
be controllers with the same address on the same line. Address 255 can be used
by the Master to communicate with all connected equipments (broadcast mode),
while with 0 all devices receive command, but no answer is expected. ATR171 can
introduce an answer delay (in milliseconds) to Master request. This delay has to be
set on parameter 85
Se. d e.
. At each parameters modification, instrument stores
values in EEPROM memory (100000 writing cycles), while setpoints are stored with a
delay of 10 seconds after last modification.
N.B.: Modifications made to Words different from those described in the following
table can lead to instrument malfunction.
Modbus RTU protocol features
Baud-rate
Selectable on parameter 83
bd . rt.
4.8 k
4800 bit/sec
9.6 k
9600bit/sec
19.2k
19200bit/sec
28.8k
28800bit/sec
38.4 k
38400bit/sec
57.6k
57600bit/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 find all available addresses and
functions:
RO = Read Only R/W = Read / Write WO = Write Only
To Next Page
Loading...
Need help?
General
