Elk M1 - Can I Drive Exterior Speaker, Strobe, Interior Speakers AND Screamers?


Active Member
Hello Coccoon Elk M1G experts. Can you help me figure out the best design to drive an exterior speaker with attached strobe, interior speakers, and interior screamers? The strobe should have different timing and condition logic than the exterior speaker. The interior screamers should have different timing and condition logic than the interior speakers and exterior speaker.
Here’s the design I came up with to drive all four. What do you think? Will this work?
The components:
  • 1 x Elk 1RT Outdoor Speaker (exterior on garage)
  • 1 x Elk SL1 Strobe (attached to 1RT) (exterior on garage)
  • 3 x Elk TWSF Flush Mount Speaker/Microphone (interior)
  • 1 x Elk RB Relay Board (main can with M1)
  • 1 x Elk TWA Amplified Two Way Listen In Interface (main can with M1)
  • 5 x Moose/Sentrol/Interlogix MPI-47E Piezo Screamer Sirens (interior)
  • 1 x Altronix eFlow4NX auxiliary power supply with Elk 1280 battery.
The power budget:
  • Elk: 1.3 A Peak, 52% of rating. Powers the Elk M1 chassis; M1KP2 keypad; M1XIN 16 zone expander; M1XSP serial expander for Uplink radio; 1RT speaker; SL1 strobe; M1PCSPIM UPB Interface; 3 x Bosch ISC-BDL2-WP12G Blue Line.
  • Altronix: 2.6 A Peak, 65% of rating. Powers the M1XRWTW wireless transceiver; M1TWA; M1XEP ethernet interface; glass breaks; screamers; Uplink 4500ez. 
Power Budget Spread Sheet Below (Click to Expand):
Power Budget.jpg
The approach:
  • Output 1 is unused. The TWA drives the speakers instead of Output 1.
  • Output 2 drives Elk 1RT Speaker
  • Output 3 (dry contact relay) drives Elk SL1 Strobe with power from Elk VAUX.
  • Relay Board, Relay 1 NO contact drives Screamers with power from Altronix aux supply.
  • Interior speakers and microphones are driven from the TWA Amplified Two-Way Listen In Interface.
Does this design and load split make sense?
I'm concerned about the RB relay board. It is normally driven from jack J16 on the Elk M1, but I can't use J16 to drive the RB because I have to use it to drive the TWA via its jack J4.
But the TWA DOES have a pass-through from J4 to J3 to expand the bus. Can I successfully daisy-chain the TWA to the RB relay board by connecting J3 on TWA to J1 on RB? If I daisy-chain, can I address the RB correctly through the TWA?
Is there any other way for an RB to co-exist with a TWA on the Elk M1G?

NOTE: I cross-posted this from Forum "Home Automation/Microcontrollers" which doesn't seem to have much traffic. I want to delete it there and keep it here.

Thanks in advance,
For some reason, I think your power calcs are way off. I want to say you've only have 1A of aux on the M1. Also, you don't size the panel or power supply for standby only, it's sized for full alarm condition of every device and typically there's a 20% headroom left as a best practice. The batteries should also be sized to meet or exceed the standby of the host panel.
Power sizing isn't a % of the output, you figure worst case alarm + 20% then put load accordingly.
You wouldn't drive the strobe off OUT 2 no matter...unless you chose a voltage output and a dedicated siren design instead of a speaker.

Then how you drive the outdoor horn is based off the system and good neighbor feature (as well as the amp on the M1). The strobe and piezo are rules based and the TWA/interior speakers are driven via the TWA event. Honestly, with TWA, I fail to see the point of the screamers since you're not going to be able to really use the TWA. I did a quick scan and it doesn't appear you'd be able to kill that output based strictly on rules. The closest conditional I saw was audio amp, which I think isn't going to fit the bill, as you need to kill that output on TWA start.


Active Member
I have two power columns, standby and full-load (i.e., full alarm condition). All battery sizing and backup time calcs are based on the full-load, i.e., with everything at full operating amps (RF comms, strobe, speakers, motions, etc). I estimate 48% headroom on the Elk power supply and 35% on the Altronix aux power supply.
I estimate 3 hours off the aux power supply at full-load, but, in reality, it will be a lot more because the TWA, screamers, and Uplink radio won't be operating but for a few minutes, certainly not 3 hours. 
The strobe is off of Output 3, not 2.
Good point about the microphone inputs being useless if the screamers are activated.
So, is there an alternative design concept where I can drive all exterior speaker, interior speakers, screamers and strobe?