AlieLeite

Hi... I am no expert, but many panels put out -24 volts when the panel is normal in order to supervise the NACs. If you reversed the + and - terminals on the panel or sounder this may be causing the issue. I don't know about Apollo equipment so this may not be the case, I also do not know how these panels are supervised, do you have EOLRs installed if they are required? assemblage PCB