VISORNET - Installation
I-10
Doc. DM245-I
Rev. 7.0
especially useful in avoiding potential difference problems between masses). This is
applicable both for the input with current source as well as voltage source. In cases of
connecting a voltage source, the device is able to detect the presence of voltage
between 3 and 30 V. A priori the idle state of the device is unknown as this is
selected as activation when the source disappears (V<2V), which also permits
sabotage detection. You should not exceed 30 V in order to prevent damaging the
device.
Current source
An optic insulation also exists in this case. The current ranges that are detected are
between 2mA and 40mA inclusive. The standards to follow are the same as those
given above.
I - 2.2.2. CLESA
CLESA, (Control de Líneas de Entrada/SAlida) the input/output lines control device,
has two main functions. First, it collects information coming from external devices,
i.e. the opening or closing of a relay (depending on whether it is usually open or
closed), and the absence or presence of voltage or power supply. The device is
able to detect sabotage in the inputs, whether it is carried out by connecting the two
input wires or by cutting one of them. To achieve this, the connected external device
must be prepared for supervised input. The inputs/outputs device is ready to work
with normal inputs as well as supervised inputs. Secondly, the CLESA module is able
to control external devices via the opening/closing of a relay. Each output has three
contacts: COMMON, USUALLY OPEN and USUALLY CLOSED. Consequently
the CLESA is ready for devices that activate when a relay closes or for those that
activate when it opens.
The CLESA module has 6 inputs and 6 outputs. The information received from the
inputs, or the one transmitted to the outputs, is exchanged with a remote center (i.e. a
PC with a control program) through a twisted pair. The transmission is carried out
through an interface in accordance with the RS-485 regulation (balanced data
transmission). This permits you to transmit data at a longer distance than the RS-232
regulation.
Due to the transmission characteristics of the RS-485 interface, it is possible to place
several input/output boards over the same twisted pair, resulting in a modular
system. According to the user’s needs, it can have 6 inputs and 6 outputs, 18 inputs
and 18 outputs, etc. . In this case, the center controlling the device, distinguishes
which of the modules it is dialoguing with via its identification number. This number
is programmable in each device with a microswitch located inside. This number must
be individual to each device connected to the same wire.
Functional blocks
The diagram of device blocks is as follows:
