does anyone of you have a copy of the IP/RS232 protocol for these units ? I cannot find it anywhere.
An anywhere you should look is Google. I googled "SONY VPL-VW570 RS232 PROTOCOL" and got a page full of links to the full documentation. You can too.
really ???? can you share one of the links with us as I cannot still find it ?
Few are labeled specific to the 570/270, but many generic and one on point for the 520 which is virtually the same unit. Sony doesn't change their control codes (IR or Serial) for years at a time. So try these;https://support.justaddpower.com/kb/article/22-sony-rs232-control/https://www.digis.ru/upload/iblock/53c/VPL-VW320, VW520_ProtocolManual.pdf
I scanned through about 8 models of the last 10 years, all used the same commands. A very few added some new feature command along the way. Try it.