Keyence PLc With Mountz Screw Counter

Hi I am new to Keyence I have a Mountz screw counter that stay high until the screw is inserted it drops low on completion (0 Volts) the plc is flashing when screw inserted however the ladder is not seeing it. The Ladder has an input from the screw counter at 0009 and the ladder has a counter which I assume when the state changes it counts 1 until I hit 4 screw counts when the counter is equal to the preset of 4 it is supposed to close the counter done bit which completes the cycle but I cant get the counter in ladder to count. Any Ideas? Thanks Dwain

0005 = sets\resets Counter0 (set: 0005=1, reset: 0005=0)
#0004 = preset value, no.of counts before C0 contacts change status
0008 = count input

Thanks

Ok I see now whats going on here. I thought that AB when the Input 0005 toggled it incremented the counter here Keyence 0005 set or reset the counter 0008 does the actual counting. I didnt realize the 0008 actually incremented the counter. Realistically 0008 should be 0009 because that is the actual input to the PLC. Thanks very much for your help. Dwain