Using alarm sensors to create scenes and support a partitioned alarm system

[Handywill]

Can alarm sensors be used by two systems in parallel?  I think so, but wanted to be sure (a) that was true in practice and (b) there isn't a simpler/cheaper solution to my specific problem.
 
My problem comes from having a DSC panel with partitions.  The available Indigo plugin does not support more than one partition. I can't program in python, and the plugin originator is inactive, so upgrading the plugin doesn't seem feasible. I'm actually not looking for alarm functionality, I want to use the sensors in multiple partitions in scenes in Indigo. At the same time, I want to have the alarm panel continue to function with multiple partitions (so it can actually be used as an alarm system by occupants of each of the units in the triplex)
 
What I want to do is have the sensors report to Indigo some way that I can actually do myself (short of learning to program in python and learning the TPI.  A couple of possibilities occurred to me:
1) have the hardwired alarm sensors report to two different panels in parallel, move the Envisalink from the "parent" panel and add it to the "child", which would be unpartitioned (and simply reporting via the Envisalink to the network and on to Indigo, not reporting to my alarm monitoring company).  Is this just a matter of jumper wires between the device terminals on the two alarm boards?  (of course my existing panel has an expansion in a separate box, so it isn't that simple in practice, but...).  Cost is maybe $70-$90 for a panel with enough inputs, plus maybe $50 for programming the panel (I think I can handle with wiring myself).
2) have the hardwired alarm sensors report in parallel to a piece of hardware whose sole purpose is to make the sensors resident on my hardwired ethernet network so they can report to Indigo on the server.  I'm not sure such a piece of hardware exists, and if it does, not sure it would be cheaper than buying an alarm panel.
 
Any thoughts?

 

[LabPaddy]

In wiring 1 sensor to 2 zones, you will need to add a second eol resistor in parallel, or use half the resistance on a single EOL resistor.

 

[Del91574]

You don't want to monkey with EOLR's and all that. Most panels will see resistance values that fluctuate out of whack as a trouble condition and report as such (DSC is notorious for system tamper messages, if enabled).
 
If you're going to do a "child" system, the best option is to use the alarm contact as a trigger to a TTL DPDT relay and split the output between the two panels.
 
Can't comment about indigo or the 3rd party programs. Not enough time in the day for me.

 

[LabPaddy]

No monkey business, just some ohms law. EOLR circuit on my Vista 20P is nothing more than a voltage divider circuit into a comparator. I've used this to run a single PIR into 2 partitions for years, no issues.  The circuit can't see resistance values. It sees voltage, which doesn't fluctuate with a fixed resistor values.
 
 
 
 
 
 
I can't  imagine DSC's circuit is much different, unless they use an ADC, which would still work. But would recommend testing or measuring the voltages with single EOLR on one zone. Compare it to 2 EOLR in parallel on 2 zones. 

 

[Del91574]

No monkey business, just some ohms law. EOLR circuit on my Vista 20P is nothing more than a voltage divider circuit into a comparator. I've used this to run a single PIR into 2 partitions for years, no issues.  The circuit can't see resistance values. It sees voltage, which doesn't fluctuate with a fixed resistor values.
 
 
 
 
 
 
I can't  imagine DSC's circuit is much different, unless they use an ADC, which would still work. But would recommend testing or measuring the voltages with single EOLR on one zone. Compare it to 2 EOLR in parallel on 2 zones. 

Yes, voltage comparator, however you're forgetting basic alarm panel functionality on the back side. Without knowing how you're wired on the PIR side and tripping, I've seen and had to fix this on an install (conversion) from a DSC to a VIsta and a few other examples in the wild in the past 20 years. Yes, any good field tech would know you don't meter a protective circuit using resistance, as it doesn't tell the whole story. Learned that about 17 years ago in a class learning another product that bases it's alarm response from zone voltage (short, open, etc.)
 
In the case of a 20P, with a 2K EOLR value, if you put two resistors in parallel, you will generate a trouble condition when one EOLR is tripped, the panel will see a voltage change. If the value is close enough to the trouble value, which on a Vista is +/- 500 ohms of the EOLR value (too lazy for ohm's law at this hour) the panel will indicate a fault as a trouble (CHECK) on the keypad. If the system is armed, it will generate an alarm, but disarmed, it will be a trouble. All contained in Ademco/Honeywell's installation documentation and it factually works, and works well. It'll annunciate either a high resistance or low resistance fault which is required by UL on the listing of the panel. If you haven't generated a trouble condition, you've been lucky that your voltage values are probably high enough to be within the window.
 
It's generally a bad idea to play with double EOLR's in this manner as you may have enough voltage to be within tolerance to not generate a trouble, or you may not. In the case of DSC with a 5.6K EOLR, you're not going to have enough voltage to keep the panel happy within it's trouble tolerance.

 

[cobra]

If you're going with a second panel anyway, you could use instead a panel that has DSC integration.  I know HAI/Leviton Lumina/Opti automation panels do that.  You hook up serial between the DSC and the automation system and it can see all the security sensors.  (The states are shared without having to worry about wiring sensors in parallel.)  There may be other panels that can do that as well.
 
But if you want to stick with Indigo only, maybe that's not an option.