New emonPi install questions

I’m a brand-new emoncms user and emonpi owner (received yesterday, order #16007). I want to ask a couple of questions and offer a few observations.

I’ll start with the questions and leave my soap box for last.

I live in North America and I purchased the bare emonPi along with two CT clamps, AC-to-AC adapter, and emonPi power supply. I wanted to use an existing PI 3 so I didn’t buy the fully assembled enclosure with LCD or preloaded SD card.

I used the Etcher tool to burn emonSD-07Nov16 to a 32GB flash card formatted for MS-DOS FAT.

I have a clamp on each side/phase of the panel for my house. I’m also using the AC-to-AC adapter bought from the emoncms shop. My dryer, water heater, HVAC, and sprinkler pump are on a separate panel that I’m not monitoring. I do not have any solar at this time.

1 What is wrong that I have negative values? When I first started collecting data, the values were all negative. I finally “fixed” this by searching around and applying -1 to the scales line in the emonhub config file. I also adjusted the calibration line to 110v. The values in the emonhub.log file is still negative but the UI shows correctly. I have tried flipping the CT claps over and still have negative values.
2 Do I need to do any further calibration? I see some forum posts for calibrating based on known loads like an iron or light bulb but they appear older and not necessarily related to the emonPi with the approved CTs bought from the online shop.
3 I have different kwh rates based on the time of day with my utility company. So, I installed the Time of use – flexible app. I started logging yesterday evening during the medium period so it hasn’t been a full 24 hours yet but I’m seeing negative kwh readings in the medium and high categories. Is that ok? My tiers are low, medium, high. Low time runs from 11PM to 6AM the next morning. Medium runs from 6AM till 1PM and High is 1PM till 6PM. My rates are 8.3 cents for low, 10.5 cents for medium and 18.6 cents for high. Here are my settings: Tier names and costs: Low:0.083,Medium:0.105,High:0.186 Weekday Tier Start Times: 0:0,6:1,13:2,18:1,23:0 Did I get those setup correctly?
4 Because I’m not using the emonPi enclosure with LCD, I disabled the LCD service. I also disabled the openhab service. I’m curious what has dependencies on the apache2 and nodered services?
5 If I do decide to buy the enclosure and LCD…where can I find it? I did a quick look on the shop page and didn’t see an option to order the bare enclosure and LCD assembly only.

Here are my files:

emonhub-config.txt (7.2 KB)
emonhub.log.txt (1.1 MB)

Now that my questions (for now) are out of the way. Having been around the web long enough, I’m sure some will probably want to reply something along the lines of RTFM. I understand your sentiments. Moving on…

I do want to comment on my initial unbox and setup experience because I love this idea and want to help make it better.

I’m sure that most people purchase the emonPi assembled with a pre-loaded SD card. For that scenario, the site guide and documentation is fairly straight forward and decent. But in my scenario, there is a lot that is left out IMHO.

The first issue I ran into was assembly with an existing Pi 3 I had laying around. I ended up looking through the youtube channel to find the correct layout with the emonPi board on top and the PI on the underside. Having worked in the IT industry for 20+, when you leave users to figure things out, they can come up with something that makes perfect sense to them but was never how it was originally intended. I’m just simply asking for a quick drawing or picture to be included because as a typical person, I only read the directions when I’m stumped. This little detail could have saved me time and frustration poking around the forum and youtube channel.

The second issue is related to the guide and pre-built SD card images. To get the prebuilt SD card image on to the card, I had to visit and follow no less than three different pages and “sub” guides. I just feel that the guide could provide the basic overview and steps before pointing me to a link that takes me away from the site and the guide for obtaining the Ether software, card image, and etc…

Third issue was that following the guide, I was expecting the emonPi to show up in my wifi networks list so that I could configure it following the setup routine. This never happened for me which lead me on a chase searching through the change logs to find the default SSH username and password so that I could SSH into the PI to figure out what was going on. I did eventually find the credentials page after the fact but I feel that it is buried under too many clicks/links. I did a site search as well as a google search with little luck. It also wasn’t very clear that the very first time I login to emoncms web interface, I’m expected to click the register link first to create a local account. This also had me searching for a default account only to see a comment that someone needed to click the register link to create a single, local, account first.

Fourth issue was that once I had the image on the card and everything booted, I had to find forum posts on the recommended steps for updating the underlying software as well as emoncms. Once I realized the CD card image was almost a year old, I set about searching for the recommended way to keep it up to date without breaking things. I ended up running: sudo apt-get update && sudo apt-get upgrade followed by sudo apt-get dist-upgrade and then I went into the emoncms UI and clicked the Update button under Administration. I’m curious if there is anything else that I could or should be running in the form of update commands??

All of those issues out of the way and I now in the emoncms and trying to get it setup. I noticed that in the Inputs screen, I was getting zero values except for the vrms key. It was only after I found a forum post that said the CTs must be plugged in prior to applying power to the emonPi board did I finally get this problem solved. This is a pretty important piece of info that should be front and center in the guide.

Just my two cents and YMMV. Overall I’m really happy with the product and want to see it’s continued success!!!

Welcome, Todd.

I’m not in a position to answer questions about OEM policy, nor to address your comments about the documentation and the perceived omissions. It should suffice to say that I understand your frustration, but writing documentation that covers all levels of understanding and ability is very hard. I try to point out deficiencies wherever I can, but there, my problem is I’m too familiar with OEM thinking and designs, so it’s very easy for me to take for granted something that appears to be total magic to someone else. (Arthur C Clarke’s 3rd law: Any sufficiently advanced technology is indistinguishable from magic.)

I have drawn Glyn Hudson’s attention to your comments, and I was expecting him to have responded.

I assume you have seen the page in Learn: “Use in North America”. There, the “phase dots” on the c.t’s show the correct orientation for these. You must always plug in your a.c. adapter the same way round, because reversing that is equivalent to reversing the c.t’s. Our convention is imported power is positive.
You don’t say, I assume your arrangement is as Fig. 2, with each c.t. going to a separate input of the emonPi. I can’t add much more until I know exactly what your hardware set-up is.

Forget calibration with a light bulb. Even if it’s a high powered tungsten filament, that’s totally misguided. You need a much larger load than that, because all c.t’s are inherently inaccurate at low currents. You should calibrate at around 30% - 70% of the c.t. current rating if at all possible. But even without calibration, unless you’re unlucky and have a set of components where all tolerances conspire against you, or unless you have very low loads (c.t. inaccuracies again, and possibly noise/interference pickup too), you should be getting readings that are within about 5%.

I know nothing about the Time of Use or Apache dependencies so I can’t help there. For availability of the case, you need to email the shop.

Nice work getting up and running. Thanks for your comments.

The LCD script will attempt to auto detect an LCD at startup. If no LCD is detected script will automatically stop. Disabling it is not required. Apache2 is required to run serve Emoncms. You can disable NodeRED if you don’t want to use it. However the RasPi3 has plenty of available resources so you won’t notice a speed difference.