Using Elk P212S with M1DBH

[phareous]

I want to run one M1DBH from the M1 and a second datahub from a ELK-P212S so I can split my power usage up
 
The first hub is no problem. For the second one (from the P212S) I think I just need to run a cable from M1 J2 to the P212S so it is on the second leg of the bus (and remove the JP3 terminating jumper on the M1), and then run a wire from the P212S to the second datahub. But since the Red + terminal is a dummy, I think the outgoing wire needs to pull from the 12 Volt POS terminal, is this correct? Or I could just run a ribbon cable out of J2 and cut off the end and hook that into the DBH terminals?
 
My second question is about the negatives. I believe doing it that way the P212S and the M1 negatives are already connected right?
I also have an Altronix Aux Power supply...for the most part this stuff is independent (pirs, glassbreaks, etc.) but I do have a M1TWA on it, so I need to tie that negative in as well? Where do I hook it up to the M1?

 

[RAL]

I think you've got it right.
 
If I follow your description correctly, you are connecting things on the data bus as follows:
 
M1 ---- P212S ---- M1DBH
 
You should connect the "+" input to the DBH to the POS output of the P212S, as you described.  Just make sure that you don't connect the M1's +VKP data bus output to the POS output of the P212S.
 
If you use J2 on the P212S to connect to the data bus to the DBH, that should work fine.  
 
The ground/NEG connections of the data bus wiring will give the P212S and the M1 power supply a common reference.
 
For the Altronix power supply, if you are using it to power only devices with dry contacts (e.g. PIRs) that connect up to zone inputs, you won't need a ground reference between the M1 and the Altronix.  But it wouldn't hurt to connect them up, just in case you add something else for the Altronix to power in the future.

 

[phareous]

What would the best place to be to connect the Altronix's negative to the M1? Does it matter? I suppose I could connect it one of the DBH's terminals? Or maybe somewhere on the M1 board itself?

 

[RAL]

It doesn't matter much which ground/neg terminal you connect it to, as long as there is a good quality connection.   Normally, there is no significant current flowing through this wire - it is just providing a common signal reference point. Any of the M1's NEG terminals would be fine, or the "-" terminal on the DBH, or NEG on the P212S, since they will all be connected back to the M1's NEG.

 

[Del91574]

Make sure the terminal is NEG and not GROUND...bad things happen otherwise.