Best way to wire CP grounding wires?

[Joystick Jerk]

I'm just going over my CP setup, and I had a question about wiring the grounds. I'm using an IPAC-4, and that unit has two ground terminals on it, so I'm wondering what's the best way to use them. Take a look at the diagram below:





Would it be best to wire the various controls on the left/right of the CP together and then connect both ends of the ground circuit to one of the ground terminals, as in the top example, or would it be best to wire everything on the CP together and then connect one end of the ground circuit to one of the ground terminals, and the other end to the other ground terminal as in the bottom example?

[BobA]

Your second picture is the way you should go.  It is more fault tolerant then the first.

[SirPeale]

Your second picture is the way you should go.  It is more fault tolerant then the first.

I disagree; he's got a ground loop on each side.  If one side fails the other can still be played.

The best thing would be to incorporate both ideas at the same time.

[um3k]

More loops means more redundancy, so the first picture (with a loop for each player) can take up to two failures and still work - and any double failure (within one loop) would never cause the other loop to have any problems.   On the other hand, the multi-loop approach is somewhat more complicated to set up, and might require a little more wire.   I personally ran both of the ground terminals on my IPAC4 to a barrier strip and ran separate loops for the two players and another for misc/admin controls.   A few hard to reach controls had their own home runs right to the barrier strip.   Tons of redundancy, but fairly complicated.

I recently rewired the entire CP to use eight CAT5 cables with each one having the last contact setup as ground.   The math for the IPAC4 works out exactly (7 contacts per cable x 8 cables = 56 inputs, 2 cables per user, one for SW1-7 and one for joystick/start/coin/SW8)  This way, they are interchangable and each group of seven signal wires has its own ground loop.     However, the main reason behind using the CAT5 was to make my CP detachable using female/female "butt" connectors to link the CAT5 cables coming from the encoder side and the ones coming from the CP.  (And because I can get CAT5 cables from work for free by the shovel full!)

[BobA]

My bad.  Didn't see that the top ones were looped as well. 

[Joystick Jerk]

Great comments and ideas guys! I guess will combine both methods into one to really up the fault tolerance level.

[Malenko]

Id say do it like the first pic, but then connect the grounds on the start buttons (its what I did) since they are usually placed close together.