hi. I need to replace this proximity sensor. Can anyone tell me what specs it is so I wont be in the dark when I go to the store to buy it? is it a NPN or PNP? It is installed in a delta CTA4100A counter which can be configured to either PNP or NPN input. Can anyone tell me also what would happens if I connect a NPN sensor to a PNP input or a PNP sensor to a NPN input? Thanks