Elk making me nuts

[MarkJames]

I recently went through my Elk system with a fine tooth comb to verify termination etc.  I've got a problem that I've isolated to one branch but can't figure out where the problem is
 
I have an M1G with an M1DBHR board to allow me additional runs
 
I have 8 keypads, 3 expanders etc. but I'll limit this to where the problem seems to be.
 
On the M1DBHR JP1 is terminated properly.
 
Branch 1 has 2 homeruns on it.
JP2 is not terminated
 
Homerun 1 goes to an M1KP that is terminated.  This is keypad 1
Homerun 2 goes to my garage where the run daisy chains through an M1XIN (not terminated) and ends at an M1KPAS that is terminated
This branch is not terminated on the M1DBHR (JP2)
 
The keypad on Homerun 1 is terminated and has ID 1
The keypad on Homerun 2 is terminated and has ID 4
 
If I disconnect Homerun 2 and enroll then everything is fine.  Keypad 1 is identified and everything else (other than what is on Homerun 2) is perfect.
If I then reconnect Homerun 2 and enroll then even though I've made sure to avoid a conflict by making the M1KPAS have ID 4 I lose keypad 1  - it shows as 'missing or not working'.
 
This is driving me mental.
 
Any help would be appreciated.
 
mark
 
 

 

[RAL]

What happens if you connect homerun 2 and leave homerun 1 disconnected, and put a terminator jumper on JP2.  Do the devices on homerun 2 work ok?
 
When you have only homerun1 connected, are you placing a terminator on JP2?
 
Some things to try...
 
Move homerun1 and 2 to a different branch, and move the homeruns on that other branch to branch1.  Does the problem go with the homeruns, or stay with branch1?
 
Disconnect the homeruns from the DBHR and use an ohmmeter to measure the resistance between the DataA and DataB wires on each homerun. It should be about 120 ohms if a terminator is installed.
 
Check your wiring connections at all the devices and on the DBHR.  Sometimes, when you have 2 wires under a screw terminal, one of the wires may not be solidly connected.  The data signals are sensitive to poor connections and a bad connection on either homerun could cause problems for any other device on the data bus.

 

[MarkJames]

Thanks for the suggestions.
 
It's finally - after possibly months of things not-being-quite-right and frustration - acting as it *should*.
 
I moved the second run from branch 1 to branch 4 as you suggested and adjusted the termination appropriately
Them I renumbered the keypads starting from 16 down re-enrolling between changes so I could identify which was which with certainty
When everything was fine I renumbered them back from 1 up re-enrolling in between.
 
For some reason one of of the KPAS got it's firmware erased in so doing so I updated it.
 
At the moment all 8 keypads enroll fine and are numbered sequentially.  I'm very happy
 
Thanks for your help!
 
mark

 

[RAL]

Glad you got it working.  Sometimes these problems are really frustrating to find and fix.

 

[MarkJames]

It seems sometimes you just have to suck it up, take it all apart, and put it back together bit by bit till it breaks.  It's just so disheartening having to do that.
 
Thanks again!

 

[mikefamig]

Looking at the DBHR installation manual it appears that each data branch is treated individually when it comes to termination.
 
I believe that when you had a single KP on branch one that you should have had a jumper on JP2. (JP2 terminates branch 1). That data loop starts at the DBHR and ends at the DBHR JP2.
 
Your second branch begins at the DBHR travels through whatever devices you have there and ends at the last device in the chain M1KPAS which is terminated.
 
It seems that your original problem was that you did not have a jumper on JP2.
 
Mike.

 

[RAL]

Looking at the DBHR installation manual it appears that each data branch is treated individually when it comes to termination.
 
I believe that when you had a single KP on branch one that you should have had a jumper on JP2. (JP2 terminates branch 1). That data loop starts at the DBHR and ends at the DBHR JP2.
 
Your second branch begins at the DBHR travels through whatever devices you have there and ends at the last device in the chain M1KPAS which is terminated.
 
It seems that your original problem was that you did not have a jumper on JP2.
 
Mike.

 
The way I read it, he started off with homerun1 and homerun2 both connected to Branch1 of the DBHR.  No jumper on JP2 because the M1KP and M1KPAS each had a termination jumper on them.  Thus, Branch1 was properly terminated with 2 jumpers, yet it did not work.
 
But when he disconnected homerun2, then things worked.  But he didn't say whether he installed JP2 in that case.
 
I've been able to get a configuration to work that was not properly terminated.  Whether it works or not in such cases is just luck, and a little bit dependent on the wire lengths and number of devices.

 

[mikefamig]

Yes my mistake. I re-read the OP and he said straight out that "Branch 1 has 2 homeruns on it". Don't know how I missed that.
 
Mike.