Serial Communication - Pixsys ATR244-12ABC Manual De Instalación

9

Serial communication

ATR244-xxxxx-T is equipped with RS485 and can receive/broadcast data via serial communication
using MODBUS RTU protocol. The device can only be configured 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 parameter
318 ("Slave Address").
sL.ad.
The addresses permitted 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.
The baud rate is selected on parameter 319
ATR244 can introduce a delay (in milliseconds) of the response to the master request. This delay must
be set on parameter 321
Each parameter modification is saved by the controller in the EEPROM memory (100000 writing cycles),
while the setpoints are saved with a delay of 10 seconds after the last modification.
Changes made to words that are different from those reported in the following table can lead to
malfunction.
Modbus RTU protocol features
Selectable on parameter 319
1200bit/s
2400bit/s
Baud-rate
4800bit/s
9600bit/s
19200bit/s
Selectable on parameter 320
8N1
Format
8E1
8O1
WORD READING (max 50 word) (0x03, 0x04)
Supported
SINGLE WORD WRITING (0x06)
functions
MULTIPLE WORDS WRITING (max 50 word) (0x10)
Here below a list of all available addresses and supported functions:
RO = Read Only
Modbus
Description
address
0 Device type
1 Software version
2 Boot version
3 Slave Address
6 Baud rate
50 Slave address automatic learning
51 System code comparison for slave address automatic learning
500 Loading default values (write 9999)
501 Restart ATR244 (write 9999)
502 Setpoint storing delay time
503 Parameters storing delay time
701 First character of the custom alarm message 1
...
723 Last character of the custom alarm message 1
751 First character of the custom alarm message 2
...
24 - ATR244 - User manual
bd.rt.
("Serial Delay").
se.de.
28800bit/s
38400bit/s
57600bit/s
115200bit/s
8N2
8E2
8O2
R/W = Read/Write
("Baud Rate").
bd.rt.
s.p.p.
WO = Write Only
Read
Write
RO
RO
RO
RO
RO
WO
WO
RW
RW
RW
RW
RW
RW
RW
Reset
value
47x
Flash
Flash
Eepr/dip
Eepr/dip
-
-
0
0
10
1
"u"
0
"u"