According to the KNX system specifications, a Group Address has a width of 16 bits (two bytes). The entire Group Address range therefore allows for a maximum of 65536 entries (2^16). The Group Address with the value zero (0) is reserved by the KNX system for broadcast telegrams and can therefore not be used as a Group Address.
ETS5 supports the full 16-bit Group Address range (i.e. also addresses in which bit #15 is used). Such an address is referred to as an "extended Group Address". All extended Group Addresses together are called the "extended Group Address range". Consequently, it is possible to use ~ 65,000 subgroups in the free-level Group Address style or the use of up to 32 Main Groups.
Extended Group Addresses and Devices
Standard Devices (i.e. with no plug-in) can use extended Group Addresses in the same way as normal Group Addresses, i.e. a user can link this Group Address to a Group Object in the usual way.
Power Line Devices
As laid down in the KNX system specifications, PL devices cannot handle subgroups in a Main Group > 15 (in a 3-level Group Address style) or subgroups > 32767 (in a free-level Group Address style). In this case, ETS will display an error message and deny the connection process.
- The explicit creation of such connections is prevented.
- Changes, the results of which, lead to an address higher than specified are prevented.
ETS3 plug-ins must be executable in ETS5 without modifications. ETS5 achieves this by using a "built-in" ETS3 plug-in software compatibility layer which serves as the basis on which all ETS3 plug-ins run. This layer only supports functions and properties that existed in the ETS3 at the time. As a result, the free-level Group Address style is not supported by this compatibility mode or tunnelled from the ETS5 through this compatibility layer in ETS3 plug-ins.
Native plug-ins (native = plug-ins or DCAs designed for ETS5 only) have access to the new ETS5 properties, also including the free-level Group Address style (i.e. the information that this style is set for the project and which subgroups exist at which levels). The following table shows the effect on ETS3 plug-ins in dependence with the associated project option to hide certain areas from ETS3 plug-ins.
Project Option Details
- This setting is always enabled for newly created or imported projects (default).
- Disabling this option enables the connection of extended Group Addresses with Group Objects of ETS3 plug-in devices; the following procedure is required for this:
- Create a list of all Group Addresses with a Main Group >15 which are used by ETS3 plug-in devices.
- All Group Addresses contained in the list must manually be moved to a Main Group < 15.
- For devices without plug-ins, this setting has no effect. All extended Group Addresses are always available.
|Group Address Styles||Subgroup is?||Project Option (hide ... extended)||Visible for ETS3 plug-ins?|
|> 32767 (Main Group > 15)||enabled||Plug-in does not see this extended Group Address|
|< 32768 (Main Group < 15)||enabled||Plug-in sees this Group Address|
|> 32767 (Main Group > 15)||disabled||Plug-in sees this extended Group Address|
|< 32768 (Main Group < 15)||disabled||Plug-in sees this Group Address|
|(From the perspective of an ETS3 plug-in via the compatibility layer, Group Addresses are always displayed in the 3-level Group Address style.|