sauter Equitherm EQJW 125, Руководство пользователя

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EQJW 125: Heating controller
Communication functions
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© Fr. Sauter AG
6 Communication functions
The EQJW 125 has a communication interface which can be used for the
device bus or alternatively for Modbus communication – also via modem. In
addition, fault messages can be sent by modem to a mobile phone as SMS
messages.
6.1 Bus wiring
When constructing communication networks, the rules for RS-485 bus
systems must be observed, in particular:
Maximum length of a bus segment: 1200 m
Maximum number of devices per segment: 32
Allow for a terminal resistance (120 Ohm) at end of cable
Use twisted-pair, screened cable
Stub lines over 3 m in length are not permissible
In accordance with standard procedures, screening should be made flat at
both ends and connected with low resistivity to earth
External measures to protect against lightning and excess voltage should
be provided when wired across house limits
On the EQJW 125, it is not necessary to adhere to a certain polarity (A or
A/B).
6.2 Device bus
The device bus makes it possible to interconnect as many as 32 devices with
little effort. It is primarily used to transmit measured temperature values
(outdoor temperature and room temperature) and commands (mode change-
over). Connecting the devices requires only two wires which are attached to
the terminals regardless of polarity – to terminals 18 and 19 in the case of the
EQJW 125.
6.2.1 Assigning addresses
Each device within the group should be assigned its own bus address. The
address '1' must be assigned once within any group. To activate the device
bus, parameter CP02 should be set to '1', then the address should be set
(parameter CP04).
If a device in an operating installation is exchanged, and the addresses used
are unknown, the 'Automatic address assignment' function can be used
(CP04 =
A u t o
). The controller then searches on the bus for an unused
address and sets it as parameter CP04.
The following should be observed when automatically assigning addresses:-
All other devices in the installation must be switched on.
Only one device should carry out the function in each case.