L-INX/L-GATE User Manual
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LOYTEC
LOYTEC electronics GmbH
variables, which cannot be loaded, because the corresponding data points cannot be located
on the device, the I/O driver reports a warning in the system log and shows a listing on the
Web interface.
Since IEC61131 program and the data point configuration are downloaded separately, it may
be possible that the IEC61131 program does not match the currently active data point
interface. In this case it could be dangerous to write values onto those potentially wrong data
points. The fact that there are any variables that could not be loaded is taken as an indication
for a configuration mismatch. The
I/O Check
feature disables the I/O driver of the IEC61131
kernel automatically in this situation. This setting is enabled by default in a new
configuration. In the rare case that it is intended to have missing data points, this feature can
be disabled in the Configurator. In the system settings de-select the I/O check (see Figure
62). If the I/O driver is disabled, it can be temporarily enabled again on the Web interface
until the next reboot.
Figure 62: System settings for logiCAD I/O settings.
The project setting
Enforce cyclic output update
enables a cyclic update of output data
points, which will ensure that those output data points will contain the calculated value after
each cycle. This is the default setting. It can be disabled, if the output data point shall be
written only if the calculated value changes. In this mode the output data point can be
modified over the Web UI for debugging reasons until the IEC61131 program calculates a
new value. This mode can also be used to implement an event-style output operation.
8.4.7 PLC Conflicts
PLC output variables are cyclically updating the respective data points, which are configured
as PLC out. If those data points are also written to by other objects (e.g. output of a math
object, receiver in a connection) this will not have the desired effect. Also favorites that are
PLC out and linked to a PLC out data point will result in two different PLC output variables
writing to one and the same data point.
The
PLC Conflicts
tab provides information for detecting such write conflicts on PLC out
data points. The tab shows a list of PLC write conflicts and the writing objects, which are in
conflict with a PLC out data point. Each reported conflict line can be selected. By clicking
the
Go to data point
button
the Configurator navigates to the conflicting object.
Figure 63: PLC conflicts tab.
An example is shown in Figure 63. The user register ‘HeatExchangeON_Write’ is written to
by the PLC, because it is PLC out. But the register is also an output in the math object
‘VE01_HeatExchange’. To resolve the conflict, either remove the register from the math
object or remove the PLC out check box from the user register. For doing the latter, select