L-DALI User Manual
113
LOYTEC
Version 5.2
LOYTEC electronics GmbH
Data point usages, such as COV trend logs or math objects may specify their own COV
deltas on analog data points. These can be bigger than the data point COV itself, but never
smaller.
6.1.7
Custom Scaling
Custom scaling is applied to all analog data points when they communicate values to or
from the network. This feature can be used, if a network data point has engineering units not
suitable for the application (e.g., grams instead of kilograms). The scaling is linear and
applied in the direction from the network to the application as:
A =
k
N +
d
,
where N is the network value,
k
the
custom scaling factor
,
d
the
custom scaling offset
, and
A the application value. When sending a value to the network, the reverse scaling is applied.
If this property is enabled, the analog values are pre-scaled from the technology to the data
point. The custom scaling is in addition to any technology-specific scaling factors and can
be applied regardless of the network technology.
6.1.8 Protected Data Points
Some data points are created automatically depending on the model currently selected. They
are protected against manipulation by the user. Therefore they cannot be deleted or moved
and their properties cannot be modified. System registers (see Section 6.1.9) fall into this
category. In addition some models (e.g. L-DALI) come with a predefined interface which
cannot be changed either.
6.1.9
System Registers
The device provides a number of built-in system registers. They are present without a data
point configuration. The system registers, such as the System time or the CPU load, can be
exposed to the OPC server. By default, all system registers are checked for being exposed to
OPC. To reduce the number of needed OPC tags, you may deselect certain system registers,
which are not useful in a specific project.
System registers are read-only by default. System register can also serve as a testing setup
for the OPC XML-DA communication without a network data point configuration. The
System Time
register is updated every second and may serve for testing subscriptions. The
Authentication Code
register can be used to verify writing to OPC tags.
The available system registers and a short description of their function are listed below:
System Time
: This register is an
analog
data point. It supplies the system time of the
local clock in UTC as seconds since 1.1.1970. It increments each second. Example:
1302533716.
Time UTC
: This register is a structured data point. It supplies the system time as UTC
broken down to year, month, day, hour, minutes and seconds.
Time Local
: This register is a structured data point. It supplies the system time as local
time broken down to year, month, day, hour, minutes and seconds.
CPU Load
:
This register is an
analog
data point. It displays the average system CPU
load in percent over the last minute. Example: 17 %.
Free Memory
: This register is an
analog
data point. It displays the current amount of
free RAM memory in Bytes. Example: 20522288 Bytes.
Free Flash
: This register is an
analog
data point. It displays the current amount of free
memory in Bytes of the Flash storage. Example: 8482688 Bytes.
Supply Voltage
: This register is an
analog
data point. It displays the currently
measured supply voltage in volts. Example: 15.1 V.
