BMS 240-072
Company OLEFINI in it’s continues efforts for improving its product quality and
services provided to the customers, begun producing a “program family” with which
customers will have the ability to control all air-curtains available from a central
location within a Buildings Control Room, units can hence be positioned in different
doors/areas of the building.
These can be achieved by using:
1. A propriety PC software platform designed by OLEFINI (Figure 2).
2. A LIN [Local Interconnect Network] is used as an in-house communication and
networking serial bus between each controller system incorporated within each
air-curtain. The LIN bus uses a Master/Slave approach, having one Master and
one or more Slaves. (PC master / Air-curtains slaves).
The network consists of a single-wire cable and multiple air-curtains with lin-bus
transceivers (Fig. 1). With this infrastructure, it’s possible to communicate reliably using
line lengths up to 40 meters without repeaters over a network containing up to 240*
nodes.
Air Curtain
ID=3
MASTER PC
Air Curtain
ID=4
Air Curtain
ID=...16
RS232 TO
LIN ADAPTOR
Air Curtain
ID=1
Air Curtain
ID=2
FIGURE 1
The system also can acquire operational data and issue commands to change operation to
each air curtain .
A standard PC acts as the network master and each air-curtain act as slave. To interface
the PC’s RS-232 serial port to the lin-bus network, a simple converter has been designed
.This is shown in Fig.1 as RS232 to LIN ADAPTOR. The speed and word length chosen
are 9600,N,8,1. The interface uses a 3 wire scheme (RXD,TXD,GND) from the PC side
and 3 wire scheme (PWR, LINDATA, GND ) to the network side .Since transmit and
receive are using the same physical media, communication is in half-duplex mode .
Without the PC one can easily adapt a special operator panel to control the whole
network or with the help of a modem (wired or GSM wireless ) one can control the whole
installation from everywhere.
AIR-CURTAIN
Regarding network operations the new system uses two hardware components . One is
the network id which is user programmable and assigns a unique id to each device on the
network. This selection is made through a 4 position dip-switch on the controller board.
The possible combinations are 16
The second is the electrical interface with the lin network.
Interface
(CASCADE)
BUS
LIN
MULTI-SPEED
Interface
&
SPEED
Interface
TEMPERATURE
2
FIGURE
Interface
IDENTIFICATION
Interface
LED
Interface
IRDA
Interface
KeyPad
Interface
CLOCK_CALENDAR
CPU
SUPPLY
POWER
AEROCURTAIN
Interface
PROGRAMMING
FIELD
Interface
HEATER
DUAL
-
The block diagram of the air-curtain control is shown in Figure 2 .Components involved
in network operations are highlighted.
After power-on or reset, the air-curtain mcu checks the board ID number and starts
checking the messages circulating along the network. If any messages have the matching
board address (ID), the microcontroller executes the command and sends an answer.
DIP-SWITCH DESCRIPTION
5
6
7
8
?
DIP-4
SW
4
3
2
1
S
The address is selected with the 4-position dip-switch . The different states of these pins
and the corresponding addresses are shown in Table 1.
TABLE 1 DIP-SWITCH COMBINATIONS
Dip switch positions
NETWORK ID
DIP-1
DIP-2
DIP-3
DIP-4
NUMBER
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
* Adresses over 16 are handled in a different way during the installation procedure.
NETWORK INTERFACE
For the network interface we use the 3 pin terminal block coming from the power board.
The signals used are .
1.GND which is the board ground
2. LINDATA which is the communication line carrying data
3. PWR which is a power line with reverse power protection that can provide up to 100
mA of +12 Volt power coming from the main board. This power is used for the PC to
network adapter or can be used with a small operator device to control multiple aircurtains.
This 3 wire cabling is translated to 6 wires inside the machine and fed to the cascade
board of the air curtains. This board has two RJ12 connectors that are used to extend the
cabling to the next air curtain. The following connection diagram illustrates that.
Pin 1,6 carry PWR line +12Volt @100 mA
max
Pin 2,5 carry GND
Pin 3,4 carry LINDATA
NETWORK CABLING
As we described above network uses a single line to exchange data between the master
and slave nodes as per lin standard regarding the electrical specifications.
An auxiliary line carrying power from the air-curtain can be used to power an extra
operator panel or the RS232 to LIN interface. This line is not necessary for operation
between air curtains.
We have two options for the cable.
a. Low cost telephone cable with 6 lines
b. Shielded ftp cable for increased noise immunity and in cases long runs of
cable are required .The outer shield should connect to each air curtain
GROUND POINT .
In case we don’t need power only 2 signal lines are required namely LINDATA,
GND. In this case we can used a very thin shielded cable or 4 line telephone cable
With a few changes, the system can be electrically isolated to provide more noise
immunity in industrial applications
Software implementation
The heart of the system is focused in our propriety software program called: BMS240072 with which the building manager has the ability to communicate and control up to
240 air-curtain units independently, view air-curtain status e.g.





Open and close the air-curtain units (ON/OFF operation),
Control fan rotation speed,
Adjust the desired room temperature,
Monitor location temperature*.
Also view a status summary of selected air-curtains
The terminal software is designed with an overview to be user friendly. Hence controlling
the air-curtains can be done with minimum computer knowledge.
Figure 3: Overview of OLEFINI’s BMS control software program.
In Figure 3 an overview can be seen of some of the basic control functions the software
program has in order to control the air-curtains. The LIN Interface has been designed to
communicate only with our latest electronic boards that will soon be incorporated
in our Air-Curtains.
NETWORK specifications
Electrical specifications
: COMPLY to LINBUS
Network topology
: multi-drop bus.
PC INTERFACE
: Serial RS232 port.
Serial data format
: 9600,n,8,1
NETWORK requirements
PC equipped with an RS232 port or usb to RS232 interface
Software
: Windows 98 , windows 2000, windows xp
Speed minimum
: 2 GHZ Pentium iV with 512 mb ram
Space requirement
: 5 mb disk space.
Connector
: RJ12
used
Distance without repeaters : 40 meters
Cable used
: telephone flat 6 lines or shieled ftp cable
Max nodes supported
By software
: 250
Max number of nodes
Without repeaters
:16