Picture below shows a overall testboard for PA-System:

What can be seen is:

Pressurized Air Drive with magnet valve and 5/2 way manyfold at low side of picture
2 Groups of three endposition switches close by
Six Fold Node (SFN) central in picture
4x PA-Terminals sourrounding SFN
single control cable (here colored flat ribbon)
double body control cable to “Demo-PLC”
Demo-PLC relais based at top of picture with status LEDs (Euro card 100mm x 160mm, euipped for one active channel)
LANTRONIX RS485 to Ethernet converter (distant counter read out)
4x 6V Batteries (for serving primary 24V for standanlone supply, not used yet)