User Manual

Functions
KNX communications
4
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● If the built-in temperature or humidity sensor fails and no external temperature
sensor is connected, fault message Er1 displays on the thermostat. If
EEPROM is damaged, fault message Er2 displays on the thermostat. Replace
the thermostat if you want the room temperature to be measured.
● If external / remote temperature sensor fails and no external sensor is
connected when input X1/X2/U1 is configured as AI except room temp external
sensor/return (AI), fault message Er3, Er4 or Er5 displays on the thermostat.
Check related sensor input terminals.
Fault Thermostat Fault information on bus
Display Error code Default fault text
Built-in sensor fails
and no external
sensor is
connected
Er1 --- ---
EEPROM is
damaged
Er2 --- ---
External / remote
sensor error
Er3 101 [N.X1] sensor error
External / remote
sensor error
Er4 102 [N.X2] sensor error
External / remote
sensor error
Er5 103 [N.U1] sensor error
For fault status messages on the bus, see Fault and alarms function on KNX
[➙ 95].
4.12 KNX communications
The RDG2..KN thermostats support communications as per the KNX specification.
S-Mode Standard mode; engineering via group addresses.
LTE-Mode
Logical Tag Extended mode, for easy engineering, is used in
conjunction with Synco.
4.12.1 S-Mode
This mode corresponds to KNX communications.
Connections are established via ETS by assigning communication objects to group
addresses.
4.12.2 LTE-Mode
LTE-Mode was specifically designed to simplify engineering. Unlike with S-Mode,
individual connections (group addresses) need not be created in the tool. The
devices autonomously establish connections.
The following circumstances are predefined:
● Every device or subdevice is located within a zone
● Every data point (input or output) is assigned to a zone
● Every data point (input or output) has a precisely defined "name"
Fault “Er1, Er2, Er3, Er4,
Er5” on display
Definitions