Pixsys ATR 121, Руководство пользователя

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ATR121/141 - User manual
11 Serial communication
ATR121/141 is equipped with RS485, it can receive and
broadcast data via serial communication using MODBUS RTU
protocol. The device can be configured only as Slave. This
function enables the control of multiple devices connected
to a supervisory system. The RS485 line must be free of LT
termination resistances to avoid malfunctions.
Each controller will answer to a master query only if the query
contains same address as on parameter
add
|
add r.
.
The allowed addresses range 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
the connected equipment (broadcast mode), while with 0 all
the devices receive the command, but no answer is expected.
ATR121/141 can introduce an answer delay (in milliseconds) to
master request. This delay has to be set on parameter.
d e.s
|
dL.sr.
(default 20ms).
At each parameter configuration, the device stores changed
values in the EEPROM memory (100000 writing cycles), while
setpoints are stored with a delay of 10 seconds after last
modification. nB : modifications made to words different from
those described in the following table can lead to instrument
malfunction.
Baud-rate
Selectable on parameter on par. 30
bd. r
|
bd. rt.
MD.1
|
md b.1
= 300bit/s
MD.2
|
md b.2
= 9600bit/s
MD.3
|
md b.3
= 19200bit/s ( default )
MD.4
|
md b.4
= 38400bit/s
Format 8, N, 1 (8bit, no parity, 1 stop)
Supported
functions
WORD READING (max 20 words) (0x03, 0x04)
SINGLE WORD WRITING (0x06)
MULTIPLE WORDS WRITING
(max 20 words) (0x10)