More than 2 data lines: more than 2 terminations?

I see in the M1 guide that I should only use 2 data lines, and max of 2 EOL terminators (one on each run).  But what if I need to have 4 data lines in my house.  Can I?  And do I still EOL terminate each run, or only do it for 2 of them?
 
Thanks,

You can only connect two data lines directly to the M1 and each one should be terminated at it's end. If you want a third physical cat cable leaving from the M1 enclosure then you have to run one of those original two original lines back to the M1 to feed the third line.
 
It's not as bad as it sounds though. The return data lines do not require an additional cat5 cable. For the return trip back to the M1 you just use a spare twisted pair from the same cable that you ran out from the M1. In other words, the green twisted pair of one cat5 cable carries DATA A and DATA B out to a device and then the blue and blue striped pair of the same cable can carry the DATA A and DATA B back to the M1 where they can be spliced to teh green pair of a new cat5 cable that leaves the control and goes to a new location.
 
A DBH is a hub that can be installed in the M1 enclosure that simplifies the connections.
 
Check out page 12 of the M1 installation manual and the instructions to the DBH for details.
 
Mike.

I should have also mentioned not to forget that the M1 control has a termination jumper on it that needs to be removed if you have two data lines connected to the M1. There should only ever be two termination points on the data bus. If you have only one data line leaving the M1 then the termination is on the M1 and on the end of that one cable. If you have two data lines leaving the M1 then you remove the  termination from the M1 and terminate at the end of the two lines.
 
Mike.

Thanks!  Yes, I plan to run CAT5e for data lines, and until you explained it, I never understood what people meant by using extra wires for data.  You are basically creating a return loop with a single bundle of wires.  Ingenious.  Only issue then is not going too long since I have effectively doubled the length.  
 
And thanks for the reminder about terminators.  I need to double check the installation in my other house where I cannot recall if I did this correctly.  
 
Thanks!!!

A sure fire way to check for proper termination  and connectivity is to power everything off and put your ohm meter across DATA A and DATA B on the M1 control board. You should get 65 ohms +- 10 ohms.
 
Mike.

Here there has been discussions relating to methodologies of EOL termination.
 
Specifically crimped or soldered; well and values of the resistors as it not universally the same values utilized.
 
IE: the Elk M1 versus the OmniPro II EOL stuff.
 
The above noted (it was a PITA to do) I soldered using a little portable solder device my EOLs then used heat shrink tubing on them.
 
Relating just for this stuff utilized 22/4 and 22/2 wires.  CatXX was also utilized.  The skinny wires are much more easier to use in the can.

pete_c said:

Here there has been discussions relating to methodologies of EOL termination.
 
Specifically crimped or soldered; well and values of the resistors as it not universally the same values utilized.
 
IE: the Elk M1 versus the OmniPro II EOL stuff.
 
The above noted (it was a PITA to do) I soldered using a little portable solder device my EOLs then used heat shrink tubing on them.

Click to expand...

Pete
 
On the Elk termination is accomplished by crossing two pins on teh device with a jumper plug and the proper resistance is built into the device. No soldering.
 
Mike.

blueman2
 
The Data lines are connected in series as we described above but the 12vdc power on the data bus should originate at the M1 control for each device to minimize the length of the runs and hence the voltage drop.
 
Mike.

 Easier to do the EOL thing individually on the Elk M1.  Thank you Mike.  I was curious about that.
 
Interesting differences between the Elk M1 and the OmniPro II.
 
Yup on the OmniPro II its a firmware option via PCA to do EOL and its all or nothing.
 
Here started initially setting the panel for auto EOL; then for whatever reasons switched over to manually installing EOL resistors.

mikefamig said:

blueman2
 
The Data lines are connected in series as we described above but the 12vdc power on the data bus should originate at the M1 control for each device to minimize the length of the runs and hence the voltage drop.
 
Mike.

Click to expand...

 
Thanks.  Good point.  Also, is it worth doubling up the power line (using 2 wires) since I still have a couple left over in my 4-pair Cat5?  
 
And Pete_c, are you talking about sensor termination or data bus termination?  I was talking about data bus. 

Thank you blueman2.  Yeah I was referring to sensor termination.  The EOL thing caught my eye.

 Yeah, EOL was probably not the right term for me to use.  I am pretty new to this.   :blink:

About voltage drop - I think that the awg23 or awg24 cat wire is fine to power most devices on the data bus in a fairly large house as long as each device has it's own lead from the power source. And Elk tells me that the system and any of their devices will run an anything between 12.5 - 15 volts. I'm not an engineer and don't remember how to calculate voltage drop over a given distance at a particular load with a given gauge of wire and I'll leave that to the guys who design the systems but when in question I do know enough to put a volt meter at the load and see what I see.
 
Mike.

You do know about the Elk DBH (databus hub), right?   While not actually needed, it can simplify things and makes less mess in the can.

sda said:

You do know about the Elk DBH (databus hub), right?   While not actually needed, it can simplify things and makes less mess in the can.

Click to expand...

 
Thanks, will look into that.  I have seen those for sale, and never really know why they were needed.  Now I do!  It would be much neater and cleaner to use jacks on all the bus wires and just plug them in.