Communication Protocol
14
Notes:
♦
RT28U adds 3 spaces
in the beginning of the response.
♦
RT28U returns decimal point
even when the value is integer.
♦
#13 (CR) is byte 0x0D;
#10 (LF) is byte 0x0A.
♦
The
U
255
command should be used
only in case just 1 slave is presented.
Protocol examples:
PC or other device:
RT28U response:
activating device number 10
U10#13#10
ok.#13#10
reading filter time
f.t#13#10
f.t 0015.#13#10
writing filter time of 30
f.t 30#13#10
f.t 0030.#13#10
reading input value of 27.5
p.v#13#10
p.v 027.5#13#10
invalid command.
command not recognized
parity error.
parity error detected
not a number.
attempt to write symbols
for numerical parameter
point error.
value resolution greater
than parameter’s one
out of range.
value out of range
unit is busy.
writing is allowed only
to device at Basic level
read only.
parameter is read-only
can't save.
problem with writing
in non-volatile memory
♦
The device remains active
until it receives another
U
х
command, but with different
device address, a
FAL
error, or with reset.
♦
Any
Baud Rate
value change
through the communication
interface also deactivates
the device.
Reading from a device
♦
If the frame consists of
only 1 word, it is recognized
as a command for reading.
♦
The device responds to it by
returning the same word and
its value, according to Table 2.
Writing in a device
♦
If the frame consists of
2 words, it is recognized
as a command for writing.
♦
With writing, transferred
are the same 2 words
that would have been
received at the respective
command for reading
from the device.
♦
After successful writing,
the device responds with
the respective command
for reading, except for
the
baud
command.
Other device responses
♦
When
Error Info
value is
-1
,
the device substitutes any
command for
error
reading.
♦
RT28U responses in case
of incorrect protocol use
are given on the left.
Reset
To reset the device,
send command
reset
.
