Remote M1DBH?

[Ira]

I will have a can installed in a detached building that will have a few expansion boards. The building will also have one or two keypads. I have a M1DBH in the main can in my home, and have run the cat5e wire to the detached building.

My question...can I have a DBH in the detached building's can if all of the jacks in the main can's DBH are not in use? It isn't exactly clear to me from the documentation if this can be done. It says I need to wire the cable between the two DBH's as a crossover cable (no problem there), but it says it needs to be plugged into J9 on the main DBH. What if not all of the other jacks on the main DBH are in use? It says "If there are more than 9 data bus cables, add a second M1DBH and connect the short CAT5 jumper (included) from J9 on the previous M1DBH board to J1 on the next M1DBH board." In my setup, I will probably have six data bus cables terminating on the main/first DBH, so J7 and J8 would be empty. Is it necessary to create a special jack to fool the DBH into thinking the unused ones are in use? If this can be done, where does the terminating plug go, since there will be empty slots on both DBH's?

So if I can do the above, are there any negatives (other than the cost for the additional DBH and the space in the can it takes up) to a "remote" DBH?

Thanks,
Ira

 

[Digger]

I believe that the documentation assumes that you have used all of the available ports and you are just adding another expander adjacent to the first.

If I remember correctly you will just plug the crossover cable into the next available port on the first hub, however, if you ever need to add anything else to the first expander you need you need to bump the crossover cable over one position so it is always plugged in as the last cable.

 

[pipeman]

The M1DBH is very convenient for wiring, but not magical or anything. It's really a simple board that loops the data bus runs in series. In my opinion, if you only have a few remote data bus items, just loop from one to the next, etc. then back to the house panel. No termination resistors, no dead ends at the remote location.

 

[Ira]

I will have at least four data bus devices to start with, and I'm sure it will grow to more. I know the remote DBH isn't necessary, but it seems to make things easier/cleaner in the long run.

Digger...if I plug the remote DBH into the first unused jack on the main DBH, where does the terminating plug go? Remote or main DBH?

Is another alternative (if I want to utilize a remote DBH) to use four of the cat5e conductors going to the remote can to wire the remote DBH directly to the M1G as a second homerun, remove the jumper on JP3 on the M1G, and terminate both DBH's at the first unused jack? That also frees up an additional pair between my home and my shop building.

Thanks,
Ira

 

[signal15]

I do this, it's works fine.

Make sure the remote DBH is plugged into the the last USED port on the main DBH. Put your terminator in the last used port on the *remote* DBH. Do not terminate the main DBH, and if you add more devices to the main DBH, you will have to move the connection for the remote DBH to the next port to make room for the new device since that connection must always be the last one on the main DBH.

Never skip a port, there can't be any open ones except for the ones after your last connection. Example:

Main DBH
1 - KP
2 - KP
3 - XSP															Sub DBH
4 - Sub panel DBH --------------------------------------------> 1
5 - Empty port												  2 - Expansion board
															 	3 - Terminator
																4 - Empty port

 

[Spanky]

You can use as many M1DBH's as you want. Make sure they are wired so the the overall data bus is in series.


The M1DBHR is the hub in which you can not put more than one M1DBHR on a leg, but you can add M1DBH dumb hubs to the M1DBHR retrofit active hub.


Remember: The M1DBH is not required, it just makes life easier to wire RS-485 data buses.

 

[Ira]

I do this, it's works fine.

Make sure the remote DBH is plugged into the the last USED port on the main DBH. Put your terminator in the last used port on the *remote* DBH. Do not terminate the main DBH, and if you add more devices to the main DBH, you will have to move the connection for the remote DBH to the next port to make room for the new device since that connection must always be the last one on the main DBH.

Never skip a port, there can't be any open ones except for the ones after your last connection. Example:

Main DBH
1 - KP
2 - KP
3 - XSP															Sub DBH
4 - Sub panel DBH --------------------------------------------> 1
5 - Empty port												  2 - Expansion board
															 	3 - Terminator
																4 - Empty port

I'm setting all this up now, but I've decided to have two "subpanels". One will be in the shop as previously mentioned. Another will be in the attached garage. I will end up with three DBH's, one in each can. Using signal15's example above that has two DBH's, it looks like I need to have the third DBH plugged into J3 on the second DBH (the one in the subpanel) and move the terminator to the first unused jack in the third DBH. Is that correct? The last used jack on the DBH in the main/first can will go to J1 on the remote DBH in the second can. The last used jack on the DBH in the second can will go to J1 on the remote DBH in the third can. The terminator will be in the last used jack in the third can. the DBH's in the first and second can will not have terminators.

Because of the way the wiring is roughed in, it would be easier if both remote DBH's could be plugged into the main can's DBH, but I guess that won't work...right?

Also, I will have power supplies (P412) and batteries in both of the remote cans. I don't want expanders/devices in the remote cans stealing power off of another can's data bus. However, the each DBH will have several expanders and/or keypads plugged into it which need power off the bus. What's the best way to wire this up? Can I simply not use the power conductors in the cat5e crossover cables between the DBH's, and then connect the "+-" terminals on the remote DBH's to their P412's outputs?

Thanks,
Ira

 

[signal15]

I'm setting all this up now, but I've decided to have two "subpanels". One will be in the shop as previously mentioned. Another will be in the attached garage. I will end up with three DBH's, one in each can. Using signal15's example above that has two DBH's, it looks like I need to have the third DBH plugged into J3 on the second DBH (the one in the subpanel) and move the terminator to the first unused jack in the third DBH. Is that correct? The last used jack on the DBH in the main/first can will go to J1 on the remote DBH in the second can. The last used jack on the DBH in the second can will go to J1 on the remote DBH in the third can. The terminator will be in the last used jack in the third can. the DBH's in the first and second can will not have terminators.

Because of the way the wiring is roughed in, it would be easier if both remote DBH's could be plugged into the main can's DBH, but I guess that won't work...right?

Hmmm. My first thought is that you would have to plug the 3rd DBH into the 2nd one. But, I think you actually might be able to plug them both into the 1st DBH. The way the DBH's are wired is that the next port doesn't become active unless you have something in the previous port that does the return on the data lines. Assuming the remote DBH self-returns, then you would have your remote DBH's plugged into the last 2 used ports on the main DBH, and then terminate whichever DBH is plugged into the last port.

If it doesn't work, and you don't want to run a wire directly from closet 2 to closet 3, you could patch the two closets by routing through the main panel.

Also, I will have power supplies (P412) and batteries in both of the remote cans. I don't want expanders/devices in the remote cans stealing power off of another can's data bus. However, the each DBH will have several expanders and/or keypads plugged into it which need power off the bus. What's the best way to wire this up? Can I simply not use the power conductors in the cat5e crossover cables between the DBH's, and then connect the "+-" terminals on the remote DBH's to their P412's outputs?

Thanks,
Ira

That works, I was doing it. But then I decided I wanted all of my power coming from one central location so I didn't have more equipment that could fail. I may have to rethink that when I put in door strikes though.

 

[pipeman]

If your remote panels are like mine, I'd still think about only the one DBH in the main panel. That leaves your terminator plug in the main panel where you can see it and make changes later without re-doing the whole thing. Just run a standard cable to the remote and series loop the A+ and B+ from remote board to board then continue the series loop back to the main panel on the A- and B-. Terminate normally in the main panel.

Sonny

Make sure the (-) leads are connected together for all panels and boards. (+) can come locally.
I also read somewhere here about using the power leads from the main panel to power a relay in the remote cans to switch off power automatically. I haven't done that yet, but I can tell you, things get weird when your system is powered up seperately.

Sonny

 

[apostolakisl]

The m1dbh is very simple, it just takes the wires from each jack and puts them into series with the same wires on the next jack down the line. You can do this manually by splicing the wires together, the m1dbh just makes it a lot cleaner, easier to modify, and quicker.

For example, a signal may go out the blue and come back on the blue/white. The dbh takes the blue/white comming back in and connects it to the next jacks blue to go back out again.

I believe if you use a crossover wire from the last open slot on the m1dbh and connect to the first spot on the next dbh, you will effectively be terminating the first dbh and making the second dbh a continuation of the first. In this event you shouldn't need to terminate the first dbh, only the second one. You can use the terminator they provide or put a resistor at your last keypad (or whatever else) on the series. For example, if the signal were returning on the blue/white in jack 3, and you put a crossover into jack 4, then the signal would be entering the next dbh in the blue/white spot where it would get passed onto jack 2 in the blue position ready to continue the path.

Keep in mind your total run length. When you use the dbh and say you have 1000 ft of cat 5 out there, you need to double that to 2000ft for you effective run. This is becuase each signal is going all the way out the cat 5 and then all the way back to the dbh before going to the next thing.