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Overview
RT284U is a low-cost multifunctional programmable controller. Its universal input
accepts the most common RTDs, thermocouples, and linear signals. The device can
be equipped with up to 2 relay outputs, which can control various actuators using
ON/OFF control algorithm, and the optional RS485 interface enables networking.
RT284U allows adjusting of the built-in digital filters and the programmable output
delay, resulting in increased operation reliability in case of industrial interferences.
Input Setting
'B' / 'H' / 'V'
'R1'
'R2'
'Q'
'S'
Communication Protocol
Notes:
♦
RT284U adds 3 spaces
in the beginning of the response.
♦
RT284U 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 one slave is presented.
Protocol examples:
PC or other device:
RT284U 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
attempt to write symbols
not a number.
for numerical parameter
value resolution greater
point error.
than parameter's one
out of range.
value out of range
writing is allowed only
unit is busy.
to device at Basic level
read only.
parameter is read-only
problem with writing
can't save.
in non-volatile memory
♦
Open the case.
'L'
♦
Follow the diagrams on the left
to find the configuration jumpers
J1 and J2, located on the main
board (cases 'B', 'H', 'V', 'L', 'R1'
and 'R1') or on the outer side of
the right board
(cases 'Q' and 'S').
♦
To set input 0...10 V,
short out J2.
♦
To set any of the other
possible input types,
short out J1.
♦
The device remains active
until it receives another
command, but with different
device address, a FAiL
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
one 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
two words, it is recognized
as a command for writing.
♦
With writing, transferred
are the same two 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.
♦
RT284U responses in case
of incorrect protocol use
are given on the left.
Reset
To reset the device,
send command reset.
Declaration of Conformity
2
Waste Disposal
Do not dispose of
electronic devices
together with
household waste
material!
Mounting
14
U
х
Electro-Magnetic Interference (EMI) Issues
Important note:
A built-in RC noise
suppression circuit is
connected in parallel
with relay contacts.
Full AC voltage
isolation is NOT
provided when relay
contacts are open.
Small AC current
(≈ 1.5 mA at 230 VAC)
still flows through
the RC circuit!
The undersigned hereby declares,
on behalf of COMECO Inc.,
that this device has been manufactured
in compliance with standards
EN 61000 and EN 61010,
and meets the requirements of Directives
2004/108/EC and 2006/95/EC.
Vladimir Sakaliyski
CEO
COMECO Inc.
If disposed of within European Union,
this product should be treated
and recycled in accordance with the laws
of your jurisdiction implementing
the WEEE Directive 2002/96
on the Waste Electrical and Electronic
Equipment.
Panel mounting ('B' / 'H' / 'V' / 'Q' / 'S' / 'L')
♦
Place RT284U into an appropriate panel cut-out.
♦
Tighten it into place using
the enclosed mounting bracket(s).
Rail mounting ('R1')
♦
Insert the upper rail edge into the upper
plastic groove of the rail-installing
mechanism on the back side of the unit.
♦
Press the unit towards the lower
rail edge until the moving part
of the installing mechanism clicks.
Rail mounting ('R2')
The device can be easily mounted on every
35 mm rail conforming to EN50022 by the means
of a standard UNDECAL socket base.
♦
All signal wires must be shielded. They must
not be packaged together with power cables!
♦
Never lay the signal wires close to inductive
or capacitive noise sources, such as relays,
contactors, motors, etc.!
♦
All shields have to be grounded ONLY at one end,
as closer as possible to the controller terminals!
♦
Avoid sharing supply lines with powerful
consumers, especially with inductive loads,
switched on and off.
♦
To stop unwelcome interference signals
entering through the power supply lines,
use shielded 1:1 isolation transformer!
♦
Shunt all switched (not only those switched
by the controller) inductive consumers with
special suppression networks: RC group and
varistor - for AC loads, or diode - for DC loads.
♦
If the controller operates in a very powerful
EMI area, it has to be mounted inside
a grounded metal shielding box!
♦
To protect the interface from electro-magnetic
disturbances, follow the RS485 standard
guidelines.
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