COMECO IA100 User manual

Specifications
Input Interface
Output Interface
Baud Rate
Supported Devices
Device Groups
Power Supply
Consumption
Operating Temperature / Humidity
Protection Class: front / terminals
RS485 for net control and data acquisition
RS232 for connection to PC
max. 9600 bps
up to 32
up to 8
mains adapter 9 VAC/DC
max. 90 mA
0...50 °C / 0...80% RH
IP54 / IP20
Warranty and Support
………………………….
serial number
………………………….
manufacturing date
QC check mark …….……(passed)
(stamp)
88 Slavyanska Str.
P.O.Box 378
Plovdiv 4000, BULGARIA
tel: [phone], 646524
fax: [phone], 646517
e-mail: [e-mail]
QD-8.2.4-WC
Warranty
COMECO warrants this product
to be free from defects in materials
and workmanship for 2 years. If your unit
is found to be defective within that time,
we will promptly repair or replace it.
This warranty does not cover accidental
damage, wear or tear, or consequential
or incidental loss. This warranty
does not cover any defects caused
by wrong transportation, storage, installation,
or operating (see 'Specifications').
Technical support
In the unlikely event that you encounter
a problem with your COMECO device,
please call your local dealer or contact
directly our support team.
COMECO Inc., P.O.Box 378, Plovdiv 4000, BULGARIA, tel: [phone], 646524, fax: 634089
e-mail: [email protected]g, WWW.COMECOGROUP.COM
IA100
OPERATION MANUAL
Please read this Operation Manual before mounting and operating!
Save the Manual for future references!
Networking
Biasing
♦When the network is in idle state,
all nodes are in listen (receive) mode.
Under this condition, there are no active
drivers on the network. All drivers
are tri-stated.
♦Without anything driving the network,
the state of the line is unknown.
The logic level at the output
of the receivers, when the line is
in this state, is '1', which, according
to RS485 specification, is coded
by at least of 200 mV voltage drop
between Band Adata lines.
♦In order for the interface adapter
to maintain the proper idle voltage state,
bias resistors must be applied to force
the data lines to the idle condition.
♦Bias resistors are nothing more than
a pull-up resistor on the data Bline
(typically +5 V) and a pull-down
(to ground) on the data Aline.
The value of the bias resistor
is dependent on termination type
and the number of nodes in the system
as well as the load impedance
of the node receiver.
The goal is to generate enough
DC bias current in the network
to maintain a minimum of 200 mV
between the Band Adata line.
♦On the other hand, to reduce
the consumption and to assure a stable
'0' state on the line, we recommend
a value of B - Avoltage drop of less
than 500 mV.
Protection against
electro-magnetic interferences
A good decision to protect the network
against inductive spikes is connecting
the signal grounds of all nodes
to the earth via 100 Ωresistors.
Networking
Wiring
♦Use two-wire half-duplex communication.
♦Note that the signal ground line
should also be connected to the system.
This connection is necessary for keeping
the Vcm common mode voltage
at the receiver within a safe range.
The interface circuit may operate
without the signal ground connection,
but in such case, reliability
and noise immunity may be sacrificed.
♦To configure the network,
use a shielded cable with at least
two dedicated pairs of wires.
The shield must be one-point connected
to the signal ground (the ground terminal
of IA100 is preferable).
♦Use one of the dedicated pairs
as a communication line
and the other one
as a node-grounding conductor.
♦Using more than 32 nodes
is not recommended.
Important note:
According to the RS485 specification,
each node has a load impedance
of 12 kΩ. Thus, the total number
of nodes is restricted to 32.
Since there are interface chips
with higher receiver load impedance,
which allow extending
the total number of nodes,
we recommend you to measure
the load impedances
during network configuration.
INTERFACE ADAPTER
v1-12.08

Connecting
♦Connect IA100 to PC
via RS232 serial port.
Note that not all
RS232 signals
should be used to create
a connection between
the adapter and the PC.
♦The RS232 part
is powered through
the communication port.
Therefore, adherence
to the data transmitting /
receiving protocol
as illustrated on the left
is crucial.
♦Since, during transmission,
RxD signal state
is undefined,
we recommend you
to clear the receiving buffer
after each transmission.
♦On the other hand, connect
the interface adapter
to the control device
network, according
to the RS485 specification
(see 'Networking').
The two IA100 interfaces
are optically isolated.
Declaration of Conformity
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 73/23/EEC and 89/336/EEC.
Vladimir Sakaliyski
CEO
COMECO Inc.
Waste Disposal
Do not dispose of
electronic devices
together with
household waste
material!
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.
Networking
Termination
♦Termination is used to match
the impedance of a node
to the impedance of the transmission
line being used. When impedances
are mismatched, the transmitted
signal is not completely absorbed
by the load and a portion of it
is reflected back into
the transmission line.
If the source, transmission line,
and load impedance are equal,
these reflections are eliminated.
♦Termination increases load
on the drivers and the installation
complexity, changes biasing
requirements, and makes
system modification more difficult.
♦The decision whether or not to use
termination should be based
on the cable length and data rate
used by the system.
A good rule of thumb is that if
the propagation delay of the data line
is much less than one bit width,
termination is not needed.
♦There are several methods
for terminating data lines.
The method we recommend
is adding a resistor in parallel
with the receiver's A and B lines,
only at the extreme ends of data line.
The resistors' value should be equal
to the characteristic impedance
of the line (120 Ωis a common value).
A termination resistor of less
than 90 Ωshould not be used.
♦Another type of termination
is through addition of a small capacitor
in series with the termination resistor.
Although this method eliminates
DC loading, capacitor selection
is highly dependent on system
properties.