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OP2: How to read current temp from sensor or PESM

firepuppy

Member
I'm pretty sure this is a very "newbie" question, but i have read all the docs and cannot find how to solve this problem:
 
The previous owner installed a couple of temperature sensors or PESMs in the house (on Zones 9 & 10) and configured them as Zone Type "Freeze".  I am not sure exactly where they are installed, but one of them has alarmed a couple of times in the last month when the house was unoccupied (heaters turned down to 50-55).  I would like to read the current temp from these devices to compare against inside thermostat temps (NOT connected to the OP2), but cannot find a way to do that.  I tried changing the Zone Type to "Temperature" and "ER Temperature" and the zone showed up under Status/Control/Temperature Sensors, but the "Current" value was always 0.
 
What am I missing?
 
 

LarrylLix

Senior Member
Is this device even an analogue device? It may just be a contact and not be capable of giving an analogue reading.
 
It may a good concept to monitor a critical  device with another device independent of the one that your anti-freeze protection depends on.
 
I use CAO Wireless Tags to monitor my fridge, and many other temperatures / humidities/ lux / door motion / etc. Each device is capable of all of these and can communicate from up to 1 km away. They use cheap CR2032 batteries that last about 8-12 months, depending on update frequency.
 
These little tags use a cloud service to accumulate data that can be accessed via PC or mobile app, can run KumoApps (javascript) and communicate via push, URL, email, and a few other methods.
 
Last I checked they run about $23 - $35 CAD and the Tag manager (one required for dozens of Tags) runs about $35 CAD. Knock off about 30% for USD.
 
Some of these tags hold years worth of data updates, while the cloud service holds everything. Charting, comparisons, even records etc...are all available online via PC or mobile app.
 
My latest conquest is my mailbox lid at the end of the lane and my fridge door open too long, checking position, temperature and light on.
 
Accuracy. IIRC  0.5c and resolution to 0.001c. Calibratable on all parameters, and triggers limits settable. URL notifications can be set to send locally only, if desired.
 
Many people use them with the ISY994 home automation controller as the are so easy to use, reliable, and accurate.
 

pete_c

Guru
 I tried changing the Zone Type to "Temperature" and "ER Temperature" and the zone showed up under Status/Control/Temperature Sensors, but the "Current" value was always 0.
 
These should show current temps if set to Temperature or Extended Range temperature.
 
Try to trace the wires to the temp modules to find the model number of said sensors.
 

firepuppy

Member
pete_c said:
These should show current temps if set to Temperature or Extended Range temperature.
 
Try to trace the wires to the temp modules to find the model number of said sensors.
Unfortunately I'm still not on site so can't trace wiring at this time...
 
I read in the OP2 Owner's manual where a "Freeze" alarm will be activated when any Thermostat or PESM detects a temperature below 40 degrees.  Since Zone 9 (which was configured as Zone Type "Freeze") shows tripped twice (and ONLY twice) in the last month, I assume the sensor is providing a temperature reading to the HAI on that zone.  Both times were early in the morning when the thermostats in that part of the house were turned way down, so I believe the alarm was real which means the HAI was seeing a temperature reading below 40F on that zone, right?  If the problem was in the wiring I would think I either get NO alarms at all OR it would be constantly alarming...

Also, I'm not sure if this is relevant, but when the zone was set to type "Freeze", the Zone status in PC Access showed a Loop value of 148, but when I changed the type to "Temperature", the Zone status showed a Loop value of 0. Is that to be expected?
 

ano

Senior Member
So maybe it helps to understand a bit about HAI hardware. Ever zone is really a mini voltmeter (0-5V) with 8 bit (256) resolution. Each zone also provides a small bit of current to each zone. (Maybe 2.9ma)
 
So if you have a door or window contact, you (typically) use a 1K EOL resister.  With the supplied current, across a 1K EOL resister, it should read back between 137-157, which translates between 137/256 (2.6V) and 157/256 (3V), and that means "secure."   
 
A temp sensor just converts temp. to voltage, and the panel has a lookup table to display temp.  The ER temp sensor is basically the same, but the temp range is wider, with a different lookup table. 
 
I checked the loop value on my outdoor ER temp sensor, and it read 0. Humidity sensor also.  I think PC Access just displays these as zero.  The only readings that matter much are contact zones.  A freeze sensor, I have no idea. 
 
So, pretty primitive, to say the least. (Think 2001 technology.)
 

pete_c

Guru
Yes here my temperature and humidity sensors all show loop values of zero.
 
So when you set the two sensors as temperature sensors and connect via PCA the values are zero under temperature sensors?
 
I replaced one outdoor temperature sensor that worked for many years that would act up or not work sometimes when it got wet or it was raining outside.  (it was under an eave).  It would show temperature values of zero when not working.
 

pete_c

Guru
Found an old thread here from 2011 relating to freeze sensors.  
 
Basically it states that only one should be configured as a freeze sensor and to use the lower zone number for the Freeze sensor.
 
You should see temperature values on either of the two anyhow.
 
hxxp://cocoontech.com/forums/topic/20192-hai-freeze-alarm-sensors/
 
Here the outside temperature sensor I mentioned earlier went bad after 15 years.  That said it was never regularly showing me temps.  The replacement is working fine.
 

firepuppy

Member
Maybe the freeze sensors I have are contact-only (2-wire) devices and are fixed to open (or close) at a specific temperature?
 
That would explain why I wouldn't get a temp reading when I tried to configure them as a "temperature sensor"...
 

pete_c

Guru
I am only aware of the OmniTemp 2 wire temperature sensors which I use here.
 
The PESM (Programmable Energy Saver Module) is used to override existing thermostats for set-back control. It also may be used for sensing and controlling other temperatures, such as attic fans, garage fans, greenhouses, basements, wine coolers, humidors, etc. It may also be used to control spa heaters with remote temperature sensor.
The PESM reports temperatures to the home control system, and has a low voltage relay and LED indicator for control. The PESM doubles as a freeze sensor, which can cause the controller to dial out in the event of a furnace failure.
For the Lumina Pro, Lumina, OmniPro II, Omni IIe, and Omni LT home control systems.
 
A OmniPro PESM uses 4 wires.  
 
1 - 12VDC
2 - Ground
3 - Zone
4 - Output
 
Temperature uses 3 wires
1 - 12VDC
2 - Ground
3 - Zone
 
If it is a humidity and Temperature sensor then it uses 2 zones for 4 wires.
 
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