M1DBH - Daisy-Chain Question

Hi,
yet another question that I have not been able to locate an answer for. Maybe you can help me point to a solution for this problem. 
 
See picture. I have an M1DBH connected to the M1G. From there I have used single runs to the various Databus Devices. Everything works fine. I have a Cat5 that runs over to the barn and has a M1XIN attached. Now we are wanting to attach a keypad in the barn too. I can't fit another Cat5 into my conduit as it is full. 
 
Can I daisy-chain the barn Databus Devices? How would I have to do this?
 
I hope you have an answer. Thanks in advance!
 
 

You can do this as long as you wire the two devices in the barn in a proper daisy chain.  The incoming Data A and Data B wires from the Cat5 cable get connected to the first device, and then go on to the second device.  Then, the 2 data bus return wires, Data A1 and Data B1 from the Cat5, also get connected to the second device.
 
Here's a picture.  Note that the Data A1 and B1 wires do not get connected to the first device.
 
Neither device should be terminated.  The termination is done on the DBH with the RJ45 termination plug.

You could also add a second DBH in the barn to allow for additional devices in the future. In that case you would just connect the DBH as the first device on the cat cable that enters the barn.
 
Mike.

Since we're talking outbuildings and distance here, I wouldn't run the bus back to the panel and I'd terminate in this case. Remember, the M1's bus is 4K' end to end, which doing a feed/return is going to put you at 2K' worth of total system wiring, which isn't much when you consider keypads and field cabling.
 
The better option here would be to split the system into two separate and terminated busses. One for the house and one for the barn. No additional cabling needed. You could do this via an additional DBH, but really it's not the best option out there unless you wire your field devices as the last on the line.