LB-762 Controller Installation Manual LAB-EL
• Hall lighting – the regulator has the possibility to control lighting in the hall, what is used e.g. at gasing operation.
• Alarm signaling device – the regulator has the possibility to signal alarm situations (e.g. inappropriate parameters of
climate in the hall, dierent breakdowns, etc.). The regulator has a suitable relay output for alarm signaling, which may
control e.g. sound signaling device. It is possible to connect alert signalling to each regulator separately, or by a joint
connection of alert outputs of all regulators in the given installation and common control with one signaling device. The
application of alert signaling device is optional. It is also possible to signal an alert via control software on a PC computer.
1.4 Data transmission network
In an installation where there is a greater number of regulators, it is possible to connect them into a data transmission network.
This network ensures cooperation with a PC computer and relevant control software. By means of a data transmission
network, the system can also perform additional functions:
• external air parameters measurement (using single thermohygrometer),
• common CO2measurement (whe single CO2sensor services many growing rooms).
The regulator is equipped with two data transmission network interfaces: Ethernet and RS-485. The application of a relevant
network is dependent upon conditions and requirements in the given installation:
• Ethernet – this network provides very high data transmission speed (10 or 100 MBit/s). Owing to great popularity of this
type of networks in any other applications, it is easy to integrate it with already existing data communication systems.
Limitation of the Ethernet network is distance – one cable section (between two network devices, e.g. between the regulator
and switch) cannot be longer than 100 meters. This does not mean that the whole network may not have greater range
– with application of proper network devices (switches, repeaters or even routers) the network can be expanded over any
area. The number of devices in an Ethernet network is relatively unrestricted – the only practical limits result from the
type of network devices used (switches) and the adopted IP network addressing class.
• RS-485 – this network provides relatively slow data transmission as compared to the Ethernet network (19.2 kbit/s),
however, its advantage is simplicity of cabling and greater scope without use of additional network devices (up to 1200
meters). As a result, cabling of networks is easier and a bit cheaper. One single RS-485 network has a limit of the number
of attached devices – from 1 to 32. network extension to a greater number of devices requires application of proper network
devices (repeaters).
Selection of the network type depends on the given installation – if it is possible to use Ethernet network, it is suggested
to use this type of network. It provides greater comfort of use (greater transmission speed of data means smaller delay in
system response, faster reading of data from regulators, etc.). If, however, the facility is very extensive and the application
of Ethernet network would require use of a number of additional network devices, boosting the cost over the benets, one
can use RS-485 network.
To ensure greater reliability, it is also possible to operate both networks. In such case, the system can use the Ethernet
network as the basic one, and in case of network failure (what is more likely than in RS-485 network owing to the need to
apply additional network devices) it would be possible to switch to RS-485 network.
1.4.1 Ethernet network
Figure1.3 presents a scheme of installation in which N LB-762 type regulators are combined by means of an Ethernet
network. The number of regulators that can be connected in an Ethernet network is practically unrestricted. The length of a
single cable section between two network devices (in a typical case, between the regulator or computer and network switch)
cannot be longer than 100 meters, but the network can be prolonged by means of relevant network devices, cascade joined
switches or routers.
Comments with regard to the method of cabling Ethernet network can be found in Section3.10.
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