PLCgen TwinCAT self-certification: build error on `SEL_LREAL`
**Test report**
| Tool | Version |
| ------ | ------ |
| ESCET | nightly-20241023-115319 |
| TwinCAT | v3.1 build 4020.56 |
| Test suite | v27 |
Setup of TwinCAT as described here: https://cstweb.wtb.tue.nl/4tc00/twincat/setup.html#twincat-install.
Project generated as described here: https://eclipse.dev/escet/cif/tools/plcgen/twincat.html#twincat-usage.
**Test case**: `timers.cif`
_Encountered errors_
The usage of `SEL_LREAL` causes build errors
- `Cannot convert type 'Unknown type: 'SEL_LREAL(timeOut, MAX((LINT_TO_LREAL(TIME_TO_LINT((preset_example_t - curValue))) / 1000.0), 0.0), 0.0)'' to type 'LREAL'` in `\Untitled1\POUs\MAIN.TcPOU` line 459
The issue seems to be resolved once you change `SEL_LREAL` to `SEL`.
Related to #1036.
Addresses #1020 #679
issue