Software
44
sysmik.de
Manual SCA-340 / SCA-340-L
4.6
Concurrent Access to the IO Terminals
Several software components can access the IO terminals of the Inline system. For
reading input data, this poses no problems. For outputs and configuration however,
the different program parts could work against each other. In order to achieve a
predictable behavior of the IOs, there is a channel-wise priority control.
Each source can set a value with its source-specific priority, or release its access.
This release is using technology specific values:
Type
Commissioning
website
Sedona
Niagara
Digital output, bool
auto
null
null
Analog output,
DALI-control, float
auto
nan (not a number) null
Measuring range, enum
auto
auto
auto
Table 4.6.1:
Release values of priority control
If several sources try to access the same IO channel, the following ranking applies:
Rank Component
1
Commissioning website (i.e. manual override in test mode)
2
Sedona
3
Niagara local access
4
Niagara remote access
Table 4.6.2:
Ranking of priority sources
The commissioning website has highest priority. Manual override is always possible
regardless of the other program components. By leaving the commissioning page,
all overrides are automatically released.
Sedona and Niagara components do by default release their priority. Only if they are
configured or connected to other components, the priority is actually used.
Note: Deleting or re-addressing components does not automatically release the
priority of this channel. Of course, a priority could be manually released by setting
explicitly to the release value. Restarting the Scalibur re-initializes (releases) the
complete internal priority array.