M1KP2 and M1DBH Wiring
- Thread starter Sifter
- Start date
It's too bad the KP2 isn't more tolerant. A bit of additional circuitry would have protected for power polarity reversal and have protect the data bus. Can someone from Elk comment on whether or not the keypads (and other bus devices) are 'mis-wiring' tolerant? It would be good to know...
So are you saying my data bus hub is also bad?
Ok, so now since the system is still expecting that keypad, its refusing to let me delete it in RP. Ive deleted it in RP, powercycled the Elk, then gone back into RP and did the enroll, and it still comes back with a conflict that the old keypad is still configured in the system, but no in the database.
KenN
Member
Just looking at the diagram from the DBH cut sheet, here's what I see happens when the RJ45 wires are reversed:
12VDC+ sourced from the DBH will be on the wht/grn rather than the brown. That will inject 12V onto the white for the keypad harness and also the wht/orng on the cat 5/6 as they are all connected together. That, in turn, injects +12 onto databus B on the keypad, and also fires +12 back to databus A on the DBH.
12VDC- from the DBH will be on the cat 5/6 green which is connected to orange on the cat 5/6 and green of the keypad. That feeds 12VDC- to the keypad's databus A and the DBH's databus B.
So I think what's happened at the keypad is that you've got a 12 VDC differential across databus A and databus B. If I recall my RS485 correctly, the protocol works on differential voltage, with 0 volts being "off state" and 1.5 VDC being "on state". The actual voltage to ground for A and B can float (within limits) but the differential needs to be within limits. So by injecting a 12V differential, you pushed about 10x the normal state voltage into the databus connections at the keypad.
It MAY have fed back to the DBH, hard to tell, but hopefully there's some isolation at the DBH module so any damage might be limited to a single port. Hard to tell without getting the details of the circuit board design.
12VDC+ sourced from the DBH will be on the wht/grn rather than the brown. That will inject 12V onto the white for the keypad harness and also the wht/orng on the cat 5/6 as they are all connected together. That, in turn, injects +12 onto databus B on the keypad, and also fires +12 back to databus A on the DBH.
12VDC- from the DBH will be on the cat 5/6 green which is connected to orange on the cat 5/6 and green of the keypad. That feeds 12VDC- to the keypad's databus A and the DBH's databus B.
So I think what's happened at the keypad is that you've got a 12 VDC differential across databus A and databus B. If I recall my RS485 correctly, the protocol works on differential voltage, with 0 volts being "off state" and 1.5 VDC being "on state". The actual voltage to ground for A and B can float (within limits) but the differential needs to be within limits. So by injecting a 12V differential, you pushed about 10x the normal state voltage into the databus connections at the keypad.
It MAY have fed back to the DBH, hard to tell, but hopefully there's some isolation at the DBH module so any damage might be limited to a single port. Hard to tell without getting the details of the circuit board design.
The DBH is passive, nothing besides circuit traces to route the 485.
As far as the panel goes, RP should give the option to send/receive conflicted items from the DB/panel, which should address the issues, however if that fails, I'd try dropping a blank template into the panel (bootstrap), enroll devices, then drop in a DB without the KP in it.
As far as the panel goes, RP should give the option to send/receive conflicted items from the DB/panel, which should address the issues, however if that fails, I'd try dropping a blank template into the panel (bootstrap), enroll devices, then drop in a DB without the KP in it.
I noticed that you have a speaker installed in the back of the flush mount box... I also have a KP2, but dont recall a speaker coming with it... In fact, I bought a Echo and have it installed near the ceiling... now i'm kicking myself...
Is this standard with the KP2, or did you repurpose another elk Speaker and install it that way?
Did the speaker tap into the OUT1/2 from the ELK directly, or was that speaker powered by the keypad?
I'm going to re-install mine this way.
Thank you.
Is this standard with the KP2, or did you repurpose another elk Speaker and install it that way?
Did the speaker tap into the OUT1/2 from the ELK directly, or was that speaker powered by the keypad?
I'm going to re-install mine this way.
Thank you.
tmbrown97
Senior Member
To clarify on the above point - the SP12 comes mounted directly to a faceplate, but there's an intended design that allows for using a screwdriver to pop the faceplate off, popping the punch-out from either the surface mount or the flush mount boxes and screwing it in there. Of course, with the surface mount box you need to make room for the magnet somehow so it's no longer a clean surface mount box - but that's beside the point.
The speaker is connected to Out1. The best way to do this is to run an 18/2 wire in parallel to the Cat5 or other keypad wire - in an ideal world. That said, some have reported that using the spare pair of wires in the Cat5 when used for the databus works just fine - it's too low a gauge officially and it requires special termination at both ends, but it perfectly doable.
The SP12 is a 32-ohm speaker which means you can parallel quite a few and still be safe within Elk's limits.
In a home with a single keypad the benefit isn't nearly as obvious, but in a really nice custom install where there are keypads at each entrance and the master bedroom, having a speaker at each keypad makes for really good sound distribution and also makes sure that the voice you hear is coming from the place where you're interfacing with the panel which makes the whole experience much better.
The speaker is connected to Out1. The best way to do this is to run an 18/2 wire in parallel to the Cat5 or other keypad wire - in an ideal world. That said, some have reported that using the spare pair of wires in the Cat5 when used for the databus works just fine - it's too low a gauge officially and it requires special termination at both ends, but it perfectly doable.
The SP12 is a 32-ohm speaker which means you can parallel quite a few and still be safe within Elk's limits.
In a home with a single keypad the benefit isn't nearly as obvious, but in a really nice custom install where there are keypads at each entrance and the master bedroom, having a speaker at each keypad makes for really good sound distribution and also makes sure that the voice you hear is coming from the place where you're interfacing with the panel which makes the whole experience much better.
I've used the extra pairs of a Cat wire. It was at a location where I originally had only a KPAS (how dumb of me not to over-wire!). It works fine since the speaker is only 32 ohms (and in my case a short run) it doesn't draw a lot of power. My biggest issue was mixing in the Elk-73 surface mount speakers I already had and trying to balance both the ohm load and output to level them off with the 32 ohm SP12. I have a speadsheet that will calculate impedance load and wattage output to each speaker when mixing and matching with serial/parallel wiring.Work2Play said: