Firmware: V2.18 / V--
26.10.2022
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6.2.2 Marker $EA2 - Variable identifier
The following naming convention has been implemented for the variable names:
The prefix
E_
is used for inputs and the prefix
A_
for outputs. For digital inputs or outputs, there is also the
special feature of providing an inverted input or output with an "inversion dash". This is necessary for the Signal
List Tool so that a "
-1
" for the inverted display is entered in the column with the marker $M. In this, the (red)
"indicator lamp" in the visualisation is only active when the input/output signal is off.
In general, you should only think in
positive
logic when programming and not check for each individual alarm
input whether it is a
normally closed
or
normally open
contact. This would reduce the readability of the program
and increase susceptibility to errors. Therefore, the following generally applies: if a digital "
connection line
" in
the program is TRUE, then this function is active, regardless of whether the physical input or output is a
normally closed or normally open contact. For this purpose, the digital signals of a normally closed contact are
inverted directly at the beginning of the processing. The following figure shows the connections:
Variable mapped to Variable name
Low
active
Application example
Physical input
Temperature sensor
x
Cable-break-proof fault signal, e.g. monitor
Virtual input
ME_<Name>
Setpoint input, manual operating level via LDSWin
Physical output
System centre - display - actual values
x
Cable-break-proof lighting control
Virtual output
MA_<Name>
Status and internal operating displays, internal alarms, locked alarms, internal
setpoints and actual values via LDSWin
The naming of the variables should be uniform and in capital letters. For example, a temperature sensor always
starts with
E_T_
. The following table shows some examples of variable names. It can be seen there that fault
messages always have the suffix
_ERR
. The frost protection thermostat has a fault message
MA_FST_ERR
with the Prio 2 message text
Frost Protection
that is locked in the controller. Locked fault messages are present
until they are acknowledged via a
group acknowledgement button
on the cabinet. Furthermore, for diagnostic
purposes, an internal analogue controller signal has been routed out to the virtual output
MW5.30
for
monitoring.