Interesting Elk M1 Gold Capability

BraveSirRobbin

Moderator
Last night's chat session consisted of David Steele (Elk's Chief Engineer), electron, smee and myself and the discussion turned to the ELk M1 Gold and its analog input capabilities.

I asked if the Elk could read analog values "directly" meaning if I placed a DC voltage on a zone input, and polled the device (via the serial port) I could get that current zone's voltage value. I would then see any change in that voltage during the next polling interval (which could be set by the user). The analog value is digitized with eight bit accuracy. The input voltage range is a maximum 14 volts (DC).

To prove this we had electron poll a zone set up as "Analog" in his Elk M1 Gold. He used terminal services as a test for communiating with Elk's serial port. He placed a worn out nine volt battery on the zone's input terminal (voltage measured 7.4 volts), polled for the device value, and registered 074 as the value.

Therefore you are able to "read" the present value of voltage on a zone set for "analog". This has some potential in the fact that you may be able to read various sensors "directly" that have an analog output voltage that is proportional to their particular measurement. For instance you may be able to read a CRMagnetics linear current sensor and use that zone as a current monitor, or maybe use a temperature probe and use that zone as a temperature monitor.

The only limitation would be in the resolution of the sensor and how it matched up to the Elk's 14 volt maximum input and eight bit resolution. Also, you would need to be able to have software that would poll these values for display in your computer system/software setup as well (if you want the real time readings displayed).
 
Therefore you are able to "read" the present value of voltage on a zone set for "analog".

I'm not sure what you are saying here. Stargate analog inputs always let you read the input value in real time and I assumed any controller with analog inputs would do this. A common application is to watch for any change in the value of an analog input, load the new value into a variable, and then speak the new value in some kind of voice alert message.

Also in the Stargte the value of all inputs is polled with each pass through the schedule (usually about 3 times per second). Why the extra code to set up polling with the Elk?
 
Let me start by saying that I don't have an Elk either... :)

If necessary, the full 8-bits can be utilized by scaling your sensor outputs to it.

Example: If you have a 0-5V signal, you could use a simple amplifier circuit to scale it up to 14V (gain of 2.8), and get 0.02V resolution instead of 0.1V.
 
Well, with the Ocelot/SECU16 combo, the analog input is converted to a value between 0-255 (0-5V), while the Elk supports up to 14V, and shows the actual voltage. Judging by the Stargate docs (page 66), the Stargate converts the voltage value to a # between 0-255 as well.
 
For clarification, any zone no matter what it is defined as, can be read for its analog value, not zones that are only defined as analog. :)
 
Yes, I was just happy that this capability existed with the Elk as it was an important one for me. It is nice that other systems such as the Stargate have it as well as USM mentioned.

Also, I'm trying to get Elk to see that there is a large outcry for home automation capabilities combined with the security panel aspects of the Elk in order to obtain more development efforts towards this curriculum. :)

As far as software, it would be cool if someone incorporated this in say a Homeseer plugin with the capability of converting the analog voltages read to "engineering units". For instance you could then read the exact current in amps from a current donut instead of the raw voltage output from that sensor.

Thanks for all the responses. The Elk is still a new unit with HA and these types of discussions are healthy for its development priorities!
 
Judging by the Stargate docs (page 66), the Stargate converts the voltage value to a # between 0-255 as well.

True but when you define a Stargate analog input you can enter a value for GAIN and one for OFFSET. These convert the RAW value (0-255) to a scaled value that is useful. This allows the value to be actual degrees for temperatures, amps for current measurement, or whatever you want to set up.
 
Also, I'm trying to get Elk to see that there is a large outcry for home automation capabilities combined with the security panel aspects of the Elk in order to obtain more development efforts towards this curriculum.

I agree we need to get Elk to focus on the automation side of the product. I think th M1 has the potential to be the "Next Big Thing" in home automation. I am worried though that they may be pursuing the "HAI Omni Pro II" market niche and not really developing the platform to replace the aging population of Stargate, Homevision, and Ocelot type controllers. I think there is a strong demand for a combination Security/Automation controller but only if it can handle all the key controller-side features (ability to speak variable values, control IR, support a non-security LCD menu keypad or touchscreen of some sort, etc) that are available on the previous generation of controllers.
 
I like the idea that one of Elk's main development engineers is a member of this forum. This show that at least they are open to ideas such as this and it's up to us to point out the capabilities that we would like in regards to HA and it's integration with our systems and security methods.

The point you make with gain and offset adjustments are what I would like to see developed into whatever software is used to interface this system be it Homeseer, mControl, etc... It would be nice to display the true "engineering" units for the sensor via software.
 
BSR,

Are you saying that perhaps something like an ADI temp sensor or some of the other bobcats might work directly with the Elk?

If you think so, I'd be will to test a few of the options out. I have plenty of parts here.....
 
Don't think those will work as they require communication with the proprietary ADI bus.

What "may" work would be a temp sensor that has a raw DC output voltage that is proportional to the temperature it is measuring. You would still have to do a math conversion of this number so it represents degrees F or C though as the reading would just represent the raw voltage reading itself.

Did this make any sense?
 
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