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Author Topic: Omnisense remote monitoring system FAQs  (Read 6875 times)


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Omnisense remote monitoring system FAQs
« on: January 30, 2014, 11:44:19 AM »
Omnisense remote monitoring system - some FAQs ....

1. The Gateway appears to use LAN or mobile data card.  If LAN does not work, then would there be an extra cost for the network card and would Omnisense supply this?
If there is doubt about having access to a LAN via cable you would need a different model gateway the G3-C-GSM wireless gateway with 3G GSM Cellular option.

Any gateway can be configured to connect to any server.  If 3G cellular is required you will need the new G-3 Gateway.

G3 cellular option
Please note that any gateway can be configured to the server.  If you require G3 cellular you will require the G3-C-GMS wireless gateway.  This gateway requires a modem simcard if the product is being connected through cellular connection.  It is suggested that a data simcard is available from GiffGaff with the best deals being a GiffGaff 'goody' bag from £5/month

2. How are the moisture sensors connected to the Gateway - are they wired or wireless?

3. Does the Gateway need a dedicated power socket?

4. We would also like to get the sensors for measuring wind speed, wind direction, rainfall, CO2 levels.
Additional sensors are available in addition to the Omnisense standard accuracy wireless sensor  S-900-1-2.0 wireless moisture sensor – please visit or contact for more information.

5. Are we able to see a file showing sample monitored data that we will get through Omnisense?
Results can be seen live and downloaded an online meeting can be arranged by request for a demonstration.

6. Would the GSM Gateway also work with LAN?
The G3-C-GSM wireless gateway works over LAN (wired Ethernet connection), WiFi (wireless Ethernet) or 3G/GSM.

7. Are we able to get the moisture sensors installed in the internal insulation or do we have to configure them first?  Do the sensors need to be configured with the gateway before installation?  Will there be some kind of software sent with the gateway for configuring it?

The only configuration required, if any, is to connect the gateway to the internet.  Gateways and sensors talk to each other "out of the box" with zero configuration.  The general process is:

1.   Create monitoring account
a.   Create job site
b.   Assign gateway to job site
2.   Plug gateway into power and Ethernet
a.   out of the box the gateway requires zero configuration to connect to the internet using your home or office LAN connection ASSUMING you have no firewall or other network restrictions in place that prevent the gateway from opening a connection to our server.
b.   If gateway’s “Internet” LED is on then its connected to the internet.
c.   If the gateway has no internet connection it will store data, up to 256K data points are stored.  Data will be uploaded the next time the gateway has an internet connection.
3.   Wait 5 minutes for first data to be read
4.   Login to your monitoring account and view your data
There is no software to install.
If you are using 3G cellular then you would need to install your SIM card and change the APN setting in the gateway’s configuration to that specified by your cellular carrier.  The instructions that come with the gateway cover this.  Again, no software is required.

8.  The wireless sensors broadcast readings picked up by the local gateway.

In case of infrequent connection to the internet the G-3 gateway holds 256K readings in its on board memory, also more memory is possible by special request. The G-900-2/GE BLD9010 gateways hold ~64K readings in the on board memory. In case of power outages or the infrequent presence of a gateway at the site where sensors have been installed it is important to note that the S900 sensor itself only stores 4 readings in its on board memory ie  the last 4 readings, as such this sensor is not designed for data logging without a gateway. However the S-16 and S-18 sensors can hold 64K readings in their on board memory: these sensors may be useful if a single gateway is moved between properties and used to collect data at intervals from several geographically separated properties eg where a dedicated on-site gateway cannot be afforded or where security is an issue or where an internet connection is not possible for some reason.

« Last Edit: September 17, 2014, 08:28:25 AM by GillR »

Andy Simmonds

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Re: Omnisense remote monitoring system FAQs
« Reply #1 on: September 14, 2015, 11:59:43 AM »
Q: Why do the Omnisense sensors sometimes read over 100% RH?

A: Towards 100% RH, sensors are only accurate to within about 5% RH, that means that, due this margin in measuring accuracy, in a high humidity environment sensors can give a reading of slightly over 100%. For example they could read 95% when there condensation is occurring i.e. the reading of 95% is describing a condensing environment which is by definition actually at 100% RH. 

The sensors that have failed in our studies (approx 5 out of several hundred) have been hovering around 100% RH for some time - sensors don't fail immediately at that RH but may do after a period.  From discussion with the manufacturer typical sensor failure under these conditions appears to result from a process led by oxidation of the tin in the circuitry, this can be visible on the tin surfaces behind the battery. In these situations, replacing the battery may not help. It is apparently less likely that the battery itself will fail and the voltage readings can of course be checked remotely.

Tim Martel

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Questions you can answer with Omnisense sensors
« Reply #2 on: September 29, 2015, 09:44:44 AM »
Simple Questions. These can all be answered by looking at the graph on the website without any further calculation:
How much moisture is in the wall, the starting ‘reservoir’?
Are walls drying out, and how fast? 
Are they drying steadily or are they occasionally re-wetted?
Is there any rot risk and if so where?
What’s the effectiveness of DPC’s
Are joist ends in good condition?
What’s the condition and effect of capillary active materials? (if you have any)
What’s the temperature across different building assemblies
What’s the humidity in crawl spaces and basements?

But with the sensors in the right position and a bit of calculation you can answer much more interesting and useful questions …..
Is there any mould risk and if so where?
How does mould risk change over time?
How likely is interstitial condensation from internal moisture? What time of year? How big is this effect and should we be concerned?
Is rain adding much moisture to the wall?
In what layer of the wall is the moisture greatest and where is capillary action taking it?
Are there any difference in the evaporation for treated and untreated walls? What’s the effect of diffusion membranes?
What’s the effect of sun on IWI systems?
What’s the effect of EWI on masonry?
Is it drying inwards or outwards and is there a specific time of day when it is greatest?

The AECB has done this for about 10 case studies in the CLR Retrofit course and is considering offering a Monitoring Analysis Service to give these answers on your project. A brochure for this is attached, if you're interested please let me know, this could be available as soon as fee arrangement has been sorted out.

Contact myself, Tim, for further information.
« Last Edit: September 29, 2015, 11:39:45 AM by Tim Martel »

Tim Martel

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Re: Omnisense remote monitoring system FAQs
« Reply #3 on: October 05, 2015, 11:06:36 AM »
How is it possible to have 105% RH and condensation at 90% RH?
Here's a very interesting extract from Physics of the Environment - A. W. Brinkman, (bottom of p6)
Relative humidity is normally expressed as a percentage by definition, RH = 100% implies that moisture is condensing. In practice droplets will tend to form on nucleating points (e.g. dust, surface asperities etc.) at lower relative humidity. It is commonplace for example, to specify 95% relative humidity (non condensing) as the maximum humidity rating for instrumentation.

The accuracy of the standard accuracy sensors is +/-5% near 100% RH, which is fine for our purposes, though Omnisense also have higher accuracy sensors which are more expensive.  This means the sensors could read 105% RH, not technically possible but within the accuracy of the readings. Also, from the paragraph above it's possible we could have condensation at what is apparently 90% RH.

A Psychrometer could be used to check the RH. I used one myself to verify RH readings a few years ago, however, I think this level of accuracy is unnecessary because
1) bricks and other hygroscopic materials adsorb significant amounts of moisture well below that RH.  There is rarely "condensation" as such in/next to these materials.
2) even next to non-hygroscopic materials we cannot expect that for a true RH of 99% next to the sensor there will be no condensation, we must allow for some local variation. If a reading is within a few percent of 100%, it's close enough for us to expect a problem.
3) you would never be able to verify the RH of a small pocket of air in a confined environment with a sling Psychrometer. There are motorised versions, even they are too big and the process of exposing the sensor would disturb the readings.
4) allowing for the factors above the accuracy of Psychrometer readings does not change the interpretation of the readings.
« Last Edit: May 18, 2016, 10:53:50 AM by Tim Martel »

Tim Martel

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Are Omnisense sensors affected by VOC's?
« Reply #4 on: January 08, 2016, 03:40:54 PM »
We recently got this from the manufacturer of the Omnisense system, suggesting VOCs (found in expanding foam sealants for example) can throw out the RH readings:
Exposure to certain VOCs may cause a permanent shift in the RH measurements.  From our experience it causes the response at high and low RH to slow, in other words put a “good” sensor in 85% RH and it will read 85% in about 5 minutes.  Put a “bad” sensor in the same conditions and it will read 82% in 5 minutes and 85% in 24 hours.  We see the same effect on the low (dry) side as well.  Midrange (40-60% RH) is unaffected.   T is unaffected. 

To minimize risks, taping would be preferred [to using expanding foam or sealants near the sensors].

If you have any questions about Omnisense monitoring, please post them and I'll do my best to answer them.
« Last Edit: January 11, 2016, 11:38:21 AM by Tim Martel »

Tim Martel

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Newcastle Uni Buildax system
« Reply #5 on: February 16, 2016, 05:03:34 PM »
Omnisense gives RH, Temperature, dew point, absolute humidity, moisture content (WME) and battery level. WME is not a common measurement but is central to our assessment of moisture risks in retrofitted buildings.  There are many other systems that do not have WME, some may be cheaper.

Buildax monitoring system can measure Temperature, RH, motion (PIR sensor), light and can have a reed switch to tell if windows/doors are open/closed. It uses 2xAAA batteries. Some details of the BuildAx platform:

Newcastle Uni are exploring uses of sensing technologies in two broad aspects 1) sustainable technologies (e.g. new energy supply or HVAC technologies) and retrofit infrastructures require different modes of use and ways of living to get the most out of them — they are interested in understanding the occupant experience of living with/in these and how this might be better supported with, for example, sensing infrastructure and new control/management interfaces; and 2) post-occupancy evaluation in terms of quantifying the indoor climate (with sensing infrastructure) and comfort, but also in terms of user experience and energy demand to investigate mismatches between design and use.

There may be an area of common interest. In our case studies we measure condensation risk but we never feed that back to the occupants. If the occupants were creating an unusually large amount of moisture which affected the walls (elevated risk of mould or condensation) the University would be interested in the effect of feeding that back to the occupants.  Such a system could be valuable in houses where too little ventilation could be creating a risk for the building fabric and/or health of the occupants.

If any AECB members are interested in this please add to the blog or contact me,, there may be some funding for sensors for this.
« Last Edit: May 18, 2016, 10:49:37 AM by Tim Martel »