** ELK-M1DBH question....

[Mp333]

I already have the ELK-M1DBH. I realize the M1DBHR would be ideal but...
My m1g is setup with just two keypads wired in to the RS485 on M1G screw terminal, I am looking to add M1XSP and M1DBH. Will probably add another M1XSP down the road. Can I use M1DBBH n my setup with bare wires for the keypad at the moment? They will be terminated with RJ45.It is a 6 wire home run to the keypad.
donot want to use all the six conductors. Since I was planning to use the spare two wires of the keypad home run for speaker. The first two keypads gets plugged into J1 & J2 with pos & neg power and A & B databus. For the return of the second keypad can I jump the databus A & B from screw terminal on M1DBH and wire them parallel into J1 & J2 RJ45? The M1XSP would be connected to J3 and J4 would have the terminating plug.

Thanks

 

[apostolakisl]

The m1dbh does not use all of the conductors.  The m1dbh is a "dumb" device which is really just splicing wires together.  It uses one pair for power, one pair to take the rs485 out to the device, and one pair to bring the rs485 signal back to the dbh so it can be spliced into the next jack on the unit where it does the same thing again.
 
So, 3 of the 4 pairs are used.  If you want to use the last pair for something else, you will need to pull it out before you crimp the rj45 plug on the end of the wire.
 
You can have 2 parallel runs off of the main panel.  So one run can go to your dbh, and a second parallel run can go directly to one or more devices run in series.  But unless you have more than 9 devices, I recommend running all of them off of the dbh.  Keep in mind that if you use the 9th slot on the dbh, you need to put your terminating resistor in manually at the last device rather than use the pre-fab rj45 with the resistor built in. 
 
EDIT:
I just re-read your post and you speak of "6 wires"  I guess this means you did not use cat5/6 wire for your home run to the keypads.  If you only have 6 conductors then you can not do this.  The only way around this would be if you could get power for your keypad locally rather than using one pair of the 6.  Also, you probably would need to manually splice some cat5/6 wire to the end of your 6 conductor wire so that you can terminate it with an rj45 since whatever 6 conductor wire you have is not likely to work directly in an rj45 plug.
 
In short, you have 2 keypads and effectively only 4 conductors going to them since you plan on saving 2 of the conductors.  This means they must run in parallel off of the board.  This means they can be the only 2 things connected without a dbhr.
 
Your choices are
1) ditch the idea of using a speaker at the keyads to free up one pair
2) get local power for the keypads to free up one pair
3) get a dbhr
4) pull more wires to your keypads, or pull a wire between your two keypads so you can put them in series.
 
 J1 and J2 are not intended for permanently connected devices.

 

[jpmargis]

The first two keypads gets plugged into J1 & J2 with pos & neg power and A & B databus. For the return of the second keypad can I jump the databus A & B from screw terminal on M1DBH and wire them parallel into J1 & J2 RJ45? The M1XSP would be connected to J3 and J4 would have the terminating plug.

 
You CANNOT do this.  Get an M1DBHR.

 

[drvnbysound]

This is exactly why I pulled a separate cable for the speakers mounted behind my keypads

 

[Mp333]

The m1dbh does not use all of the conductors.  The m1dbh is a "dumb" device which is really just splicing wires together.  It uses one pair for power, one pair to take the rs485 out to the device, and one pair to bring the rs485 signal back to the dbh so it can be spliced into the next jack on the unit where it does the same thing again.
 
So, 3 of the 4 pairs are used.  If you want to use the last pair for something else, you will need to pull it out before you crimp the rj45 plug on the end of the wire.
 
You can have 2 parallel runs off of the main panel.  So one run can go to your dbh, and a second parallel run can go directly to one or more devices run in series.  But unless you have more than 9 devices, I recommend running all of them off of the dbh.  Keep in mind that if you use the 9th slot on the dbh, you need to put your terminating resistor in manually at the last device rather than use the pre-fab rj45 with the resistor built in. 
 
EDIT:
I just re-read your post and you speak of "6 wires"  I guess this means you did not use cat5/6 wire for your home run to the keypads.  If you only have 6 conductors then you can not do this.  The only way around this would be if you could get power for your keypad locally rather than using one pair of the 6.  Also, you probably would need to manually splice some cat5/6 wire to the end of your 6 conductor wire so that you can terminate it with an rj45 since whatever 6 conductor wire you have is not likely to work directly in an rj45 plug.
 
In short, you have 2 keypads and effectively only 4 conductors going to them since you plan on saving 2 of the conductors.  This means they must run in parallel off of the board.  This means they can be the only 2 things connected without a dbhr.
 
Your choices are
1) ditch the idea of using a speaker at the keyads to free up one pair
2) get local power for the keypads to free up one pair
3) get a dbhr
4) pull more wires to your keypads, or pull a wire between your two keypads so you can put them in series.
 
 J1 and J2 are not intended for permanently connected devices.

Hmmm....
Aren't the keypads or ither devices connected in parallel using the m1dbh? The return wires that are pigtailed at the keypad seems to be in parallel with the rest of them. I would be looking to crimp the four wires for the keypad along with the two wire jumped from data bus terminal on the m1dbh that would act as te return from the keypad. All of this would crimped in to rj45. Am I missing something here?

Also Lou you mentioned
" J1 and J2 are not intended for permanently connected devices"
Can you please explain why you cannot have keypad on j1 and j2?

 

[jpmargis]

Aren't the keypads or ither devices connected in parallel using the m1dbh?

 
It might look that way, but RS-485 is a data bus.  The devices need to be connected to the data bus with a short stub.  You are proposing a long stub to each keypad which will undoubtedly cause problems.
 
I believe Lou is referring to J1 and J2 on the M1G.  The M1DBH has no restriction.

 

[tmbrown97]

It probably looks a little weird since it's 2 wires off the keypad going to 4 wires of the Cat5 but when dealing with databus, you need to think of those wires as one-way; once they get to the keypad they either need to be terminated or have another set of wires as the return path.  
 
The DBHR is the right way to do what you're trying to do - then you can terminate the keypad and not need the return path.  Anything else is a compromise vs. just biting the bullet and doing it right.

 

[gatchel]

Just as an aside, If you use anything other than twisted pair cabling you are also asking for trouble.

 

[Mp333]

Just as an aside, If you use anything other than twisted pair cabling you are also asking for trouble.

The cabling was already ran when I bought the house. It is 3 twisted pairs. I hope it is compatible for rs 485. I can try to find the specs on the canle. I have had the two keypad pads wired for few weeks without any issues.
I guess I can forgo about using the third pair for speaker...

 

[apostolakisl]

Hmmm....
Aren't the keypads or ither devices connected in parallel using the m1dbh? The return wires that are pigtailed at the keypad seems to be in parallel with the rest of them. I would be looking to crimp the four wires for the keypad along with the two wire jumped from data bus terminal on the m1dbh that would act as te return from the keypad. All of this would crimped in to rj45. Am I missing something here?

Also Lou you mentioned
" J1 and J2 are not intended for permanently connected devices"
Can you please explain why you cannot have keypad on j1 and j2?

 
 
No, they are connected in series using the m1dbh.  That is why you have to double the length when calculating the total run.  The signal goes out one pair, and back on a different pair, then out the next cat5 on one pair, and back on another pair.  Only the m1dbr puts them in parallel.  Go ahead and ohm it on the m1dbh if you like, you will see that it is just daisy chaining the data bus wires together.
 
I don't know why j1 and j2 can't be used.  If you read the instructions you will see, however, that it says for "temporary connection. . . .for testing purposes only"
 
RS-485 is pretty forgiving on wiring types and quality.  So whatever you have will probably work just fine unless you try to push the length.

 

[Mp333]

I did check it this morning and Lou you are correct.
As far J1 and J2. I meant it on the M1DBH not the M1G.

 

[apostolakisl]

I did check it this morning and Lou you are correct.
As far J1 and J2. I meant it on the M1DBH not the M1G.

 
Ahh, yes, talking about two different things altogether.  It doesn't make any difference as far as which spot you plug any device into on the dbh, only that you fill them in order j1, 2, 3, etc.  Then you put the terminating resistor on the first unused spot.   If you used all 9 spots, then you put the terminating resistor on the last device, or you could still bring the signal back to the dbh, but pull the return signal pair out before crimping the rj45 on and splice the resistor there.

 

[Mp333]

So I guess not really big difference between using m1dbh or m1dbhr aside from losing one extra device connectivity and RJ45? Plus the dbhr is active.

 

[apostolakisl]

Here is a potential solution.
 
Run one keypad directly off of the panel, in parallel with the dbh.
 
This keypad will require that you terminate the rs485 run with the resistor at the device.  This will leave you one extra pair for your speaker.
 
With your second keypad, put it as the last device on your dbh.  You will also need to terminate this keypad with a resistor at the keypad, same as the first keypad.  Now you will have the extra pair available here as well.  The only trick here at all is that you will need to splice in some CAT5 on the second keypad so that you can crimp on the rj45.  You should only splice in the 4 wires that are rs485 outbound, and power.  
 
Now your probably wondering, which pair coming out of the dbh are the inbound rs485 and which are the outbound.  The answer is, I don't know, but it's either the orange pair, or the green pair.  You'll have to either ohm it out, or just connect the one pair and see if it works, if not, try the other pair.

 

[Mp333]

Lou - You are onto something. Very good.This does make sense.Thinking out of the box..... Its either Orange or Green pair.
I wonder if I should just get dbhr and be done. Four wires to deal with. Then again what you suggesting should work....