Elk Temp Sensors & serial protocol

IVB

Senior Member
Anyone been able to successfully use an Elk temp sensor with a non-elk program (ie, MainLobby or CQC) to tell what the temp is in a given room?

I have 3 of them mounted, and I can't get CQC to display the temp. If I login via the Elk ethernet IE program, check the climate, then logout, it pushes the temp to CQC.

Before I go learn the Elk serial protocol to see if the problem is on the Elk pushing temp changes over serial side, or on the CQC side, i'd like to see if anyone has looked into this already.
 

IVB

Senior Member
Anyone?

I can't be the first guy who wants to display temperature on a MainLobby or CQC screen using Elk temperature sensors.
 

BraveSirRobbin

Moderator
IVB;

Are the temp sensors voltage sources that must be connected to an Elk zone and have that zone configured as "analog" type?

Sorry for the stupid question, but I'm just not familiar with Elk temp sensors or how they work. :)

If it's analog type, I know that HomeSeer can see that reading as a device via Electron's or MarkL's plugin. I know that MarkL's plugin even has an INI file setting where you can convert raw voltage to engineering units (such as temperature) using a typical linear slope intercept formula ( Y = mX + b ) and stuff that value into a HomeSeer device (a very wise man suggested this feature and actually helped with that part of the documentation ;) !!
 

IVB

Senior Member
Hmmm. Not stupid, actually very good question. I don't see any delineation between analog&digital either in ElkRP or in that temp sensor manual.

If Spanky doesn't see this post tomorrow and give me any clue as to how to push the temp out the serial interface, i'll post a question in the Elk forum here.
 

Steve

Senior Member
IVB said:
Hmmm. Not stupid, actually very good question. I don't see any delineation between analog&digital either in ElkRP or in that temp sensor manual.
Did you program the Zone in RP to type 33-Temperature? Thats what tells it it is analog. Then in CQC in the Driver window you need to check that sensor (red check mark) to tell CQC to poll it. You can probably also use the M1 SDK (if you have ethernet) or Hyperterm (if serial) to see the data in the stream.

I don't have the separate temp sensors but I do have the KP1 temp sensors displayed in CQC just fine.
 

Guy Lavoie

Active Member
I played around with an Elk temperature sensor using a scope and figured out how it works. It is not analog, but instead puts out actual serial data. It uses manchester encoding at just under 1 baud (!) to send the temperature as a 12 bit value. The slow data rate combined with the fast input polling of the Elk cpu allows it to decode the timing sequence. This is also why they only work on the main board inputs and not expansion boards.

You can embed the temperature value into a text string. This allows you to send the temperature values to anything that can receive a serial string and parse it to extract the temperature.
 

BraveSirRobbin

Moderator
Guy Lavoie said:
I played around with an Elk temperature sensor using a scope and figured out how it works. It is not analog, but instead puts out actual serial data. It uses manchester encoding at just under 1 baud (!) to send the temperature as a 12 bit value. The slow data rate combined with the fast input polling of the Elk cpu allows it to decode the timing sequence. This is also why they only work on the main board inputs and not expansion boards.

You can embed the temperature value into a text string. This allows you to send the temperature values to anything that can receive a serial string and parse it to extract the temperature.
Ah excellent analysis Guy. No wonder why I consider you "my idol"! :) ;) B)
 

toymaster458

Active Member
After reading the protocol I think this information is only availible when polled for. The only time Dean polls for information is when the driver first starts up and when it gets disconnected. I posted this on CQC for Dean so we will see what he says.
 

IVB

Senior Member
Cool, great analysis Guy.

I have no issues with the Keypad temps, just these temp sensors. Let's see what Dean says over on CQC.
 

frankdr

Member
Same issue here. I think IVB and I had a short thread on the CQC board about this. It looks like the temp is never sent without being requested.

-Frank
 

toymaster458

Active Member
I just posted a revised driver to the thread on CQC that will poll the temps. It will work untill Dean is able to revise the original driver.
 

Dean Roddey

Senior Member
OK, I'll update the driver. I don't poll it because everything else is sent asynchronously when it changes (as long as you have the correct notifications turned on in the Elk), so I assumed that these would be the same. I can put in a fairly slow round robin poll of the configured temp sensors. They don't have to update terribly quickly since the temp isn't going to change that fast.
 
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