MDT KNX SCN-RT1UP.01 Technical Manual page 20

Technical Manual – Room Temperature Controller SCN-RT1
The switchover of the operating modes via 1 Byte occurs by only one object, with the size of 1 Byte,
the DPT_HVAC Mode 20.102 of KNX-specification. Additional, there are 2 objects for the visualization
available, the 1 Byte object "DPT_HVAC Status" and the 2 Byte object "DPT_RHCC Status". For the
switchover of the operating modes, a Hex-value is sent to the object "mode selection". The object
evaluates the received value and switches the belonging operating mode on and the active operating
mode off. If all operating modes are switched off (Hex-value=0), the operating mode standby will be
switched on.
The Hex-values for the operating modes are shown at the chart:
The following example shall clarify how the controller handles received Hex-values and switches
operating modes on or off. The chart is to read from the top to the down.
Example:
The priority was set as
received Hex-value
0x01
0x03
0x02
0x04
Table 19: Example operating mode switchover via 1 Byte (from Version 1.2)
The DPT HVAC Status communication, DPT_HVAC Status (without number) of KNX-specification,
object sends the hex value for the adjusted operating mode. When more than one testify is valid, the
hex values are added and the communication object sends the added value. The hex values can be
read from visualization afterwards.
The following chart shows the hex values for the single messages:
Bit DPT HVAC Status
0 Comfort
1 Standby
2 Night
3 Frost-/Heat protection
4
5 Heating/Cooling
6
7 Frost alarm
Table 20: Hex-Values DPT HVAC Status (from Version 1.2)
If you heat at the comfort mode, the communication object will send the value 20 (for heating) +1
(for the comfort mode) =21.
MDT technologies GmbH • 51766 Engelskirchen • Papiermühle 1
20
Phone: +49-2263-880 • Fax: +49-2263-4588 • knx@mdt.de • www.mdt.de
Operating mode (HVAC Mode)
Comfort
Standby
Night
Frost/Heat protection
Table 18: Hex-Values for operating modes (from Version 1.2)
Frost/Comfort/Night/Standby.
Handling
Comfort=1
Comfort=0
Night=1
Night=0
Standby=1
Frost-/Heat protection=1
Standby=0
1=Comfort
1=Standby
1=Night
1= Frost-/Heat protection
0=Cooling/1=Heating
1=Frost alarm
Hex-Value
0x01
0x02
0x03
0x04
adjusted operating
mode
Comfort
Night
Standby
Frost-/Heat protection
Hex-Value
0x01
0x02
0x04
0x08
0x20
0x80