** ELK-M1DBH question....
- Thread starter Mp333
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apostolakisl
Senior Member
video321 said:
How bout that. It has been so long since I installed my dbh that those screw down terminals for the spare wires escaped my memory. And they don't say a word about them in the installation manual. But in this particular case, since he does not have cat wire in the walls, he is going to have to spice the cat wire onto his current wire, so I think it would be 6 or half dozen in this case. But with a more typical cat5/6 wire in the wall situation, it would definitely simplify using that other pair, provided you wanted the same thing at all devices.
Not true....since I retrofitted my M1 in my house for a 20P and multiple takeovers of legacy panels, no issues. We even do new installs running 8 conductor and daisy chaining the data in the panel with nary an issue, let alone errors. Nowhere does Elk specify wiring be UTP or STP.gatchel said:
They do lean towards a category cable as it's easier to terminate in RJ's for their DBH.
For the OP, no other field wiring is needed unless the XSP's are being installed "in the wild". If they're at the panel, you'd need to run a 6 conductor to them and then move your field keypads to be on the "out" from the XSP(s). Basically just feeding through the data to the KP's that have terminating resistors enabled, with 2 pairs being used at the KP.
tmbrown97
Senior Member
I'm with DEL on this one - to state that non-category cable will introduce problems is just factually incorrect. The M1 has options for retrofitting over 2-pair and straight 4-conductor non-twisted wires and it works fine. For those, the M1BDHR is the way to go if you need more than 2 endpoints.
DELInstallations said:
Work2Play said:
I guess I'm the odd one out. This is why a said what I said previously.
These are from the Elk manual:
The M1 data bus conforms to EIA RS-485 standards and operates at 38,400 bits per second.
The ELK-M1DBH † Data Bus Hub is great for new installations where it is possible run multiple CAT5 homerun cables. The RJ45
jacks allow neat and organized connections and a third wire pair is used to return the DATA lines back from each device where they
are used to feed the next adjacent jack. The M1DBH circuitry daisy chains the devices by series connecting the DATA lines A & B.
Termination is accomplished with a plug-in RJ45 terminator (supplied).
Any time RS-485 is mentioned I follow the RS-485 spec.
Any time I see the word "pair" I think paired cabling instead of straight conductors.
That's a pretty high data rate to be using the "wrong" cable on a new install. If it were 4800 I'd be less concerned.
Overall, I guess we'll have to agree to disagree on that one...what works and what's right don't always match up. Not saying it can't be done or it doesn't work sometimes, just that the better way is to use twisted pair cabling.
Also..no offense to any one that has used straight conductor cabling. If it works for you great. Sometimes the job dictates that it must be reused or whatever. I get that part...
I'll just state factual "in the wild" observations.....
We have very large sites that run 485 and 422 over very large distances for many purposes, sometimes STP is needed, sometimes UTP is needed, sometimes whatever is tossed in the pipe works. The big item is how tolerant the device(s) are to what conductors are installed. Some are pretty robust, others go down if you tap your foot.
Most of the alarm industry items, a sweeping generic term, but I'll toss out PTZ's, data for comms on access control panels and the comparatively simple M1, are pretty tolerant of various cabling types and methods. In a different comms application, sure, you may need the twisted pair, but in Elk's case, I believe it's more to facilitate easier 485 installation for the novice, as most panels don't or haven't used this technology (anyone remember the old Optex panels that did?). It's far easier for a novice or hobbyist to plug a RJ in than make the greater effort for in-out daisy....hell many guys, not just DIY can't comprehend how to properly wire a fire alarm.
In Elk's specific case (I've had many calls in to the engineers when the panel was first coming out) they were adamant that no special cabling was needed other than to maintain the topology, and I've experienced just that with many M1 installs. Their data conforms with EIA-485, however there's other items in the equation (I've had some interesting conversations about connecting an M1 via fiber for outbuildings).
In the case of the OP, for devices located out from the panel, not connected to existing KP runs, you're going to need 6 conductors pulled if you're not going to do anything with the present KP wiring. You can hop off the existing pulls, however voltage loss for the devices in the daisy is going to be an issue.
We have very large sites that run 485 and 422 over very large distances for many purposes, sometimes STP is needed, sometimes UTP is needed, sometimes whatever is tossed in the pipe works. The big item is how tolerant the device(s) are to what conductors are installed. Some are pretty robust, others go down if you tap your foot.
Most of the alarm industry items, a sweeping generic term, but I'll toss out PTZ's, data for comms on access control panels and the comparatively simple M1, are pretty tolerant of various cabling types and methods. In a different comms application, sure, you may need the twisted pair, but in Elk's case, I believe it's more to facilitate easier 485 installation for the novice, as most panels don't or haven't used this technology (anyone remember the old Optex panels that did?). It's far easier for a novice or hobbyist to plug a RJ in than make the greater effort for in-out daisy....hell many guys, not just DIY can't comprehend how to properly wire a fire alarm.
In Elk's specific case (I've had many calls in to the engineers when the panel was first coming out) they were adamant that no special cabling was needed other than to maintain the topology, and I've experienced just that with many M1 installs. Their data conforms with EIA-485, however there's other items in the equation (I've had some interesting conversations about connecting an M1 via fiber for outbuildings).
In the case of the OP, for devices located out from the panel, not connected to existing KP runs, you're going to need 6 conductors pulled if you're not going to do anything with the present KP wiring. You can hop off the existing pulls, however voltage loss for the devices in the daisy is going to be an issue.
DEL,
Good to hear about the stability of the Elk stuff. Your Elk experience is clearly more than what I have with the product.
There have been some devices I have dealt with that you could use the conduit as one of the conductors for communication if needed. It sounds like Elk falls in to that category which is good to hear.
Good to hear about the stability of the Elk stuff. Your Elk experience is clearly more than what I have with the product.
There have been some devices I have dealt with that you could use the conduit as one of the conductors for communication if needed. It sounds like Elk falls in to that category which is good to hear.
tmbrown97
Senior Member
And another trick is to pick up local power if needed as well off a remote power supply; there are often ways to cheat a little bit.
As for above - I won't argue that twisted pairs will get you the better distances with fewer errors - I was just arguing the idea that using non-category cable would automatically introduce errors - because it won't always; in many cases it'll work just fine.
As for above - I won't argue that twisted pairs will get you the better distances with fewer errors - I was just arguing the idea that using non-category cable would automatically introduce errors - because it won't always; in many cases it'll work just fine.
apostolakisl
Senior Member
If the OP simply uses the current wires and terminates the two keypads locally, one on a home run directly to the panel, and the other as the final device on the dbh, everything (including speakers) should work just fine without having to pull a single new wire or find local power.
The only thing he needs to figure out is which 2 wires on the rj45 jack on the dbh are the outbound signal. This should be easy enough to figure. With the dbh not connected to anything, plug an rj45 into j1 with a pigtail of cat5 crimped on. Short databus a/b screw terminals on the dbh with a jumper and ohm out the oranges and the greens. Whichever pair ohm to 0, these are the outbound leads. Now connect those 2 wires to your databus wires that are already going out to the keypad, along with the power leads. Then plug that rj45 as the final one in the series of devices on the dbh. The last 2 leads of the 6 lead wire get spliced to the speaker.
The only thing he needs to figure out is which 2 wires on the rj45 jack on the dbh are the outbound signal. This should be easy enough to figure. With the dbh not connected to anything, plug an rj45 into j1 with a pigtail of cat5 crimped on. Short databus a/b screw terminals on the dbh with a jumper and ohm out the oranges and the greens. Whichever pair ohm to 0, these are the outbound leads. Now connect those 2 wires to your databus wires that are already going out to the keypad, along with the power leads. Then plug that rj45 as the final one in the series of devices on the dbh. The last 2 leads of the 6 lead wire get spliced to the speaker.
I follow you. I should have elaborated a bit on my one sentence original post. I typically use 22-2PR out and back which works very well for being a non-category wire. I guess I am old fashioned in my ways at times but it always works.Work2Play said:
Non-category 22-4PR for ethernet? Not so much ;-)
