So this was a couple years ago now. Aside from doing software development, I also do nearly all the other IT related stuff for the company, as well as specialize in the installation and implementation of electrical data acquisition systems - primarily amperage and voltage meters. I also wrote the software that communicates with this equipment and monitors the incoming and outgoing voltage and current and alerts various people if there's a problem.

Anyway, all of this equipment is installed into a trailer that goes onto a semi-truck as it's a portable power distribution system.

One time, the computer in one of these systems (we'll call it system 5) had gotten fried and needed replaced. It was a very busy week for me, so I had pulled the fried computer out without immediately replacing it with a working system. A few days later, system 5 leaves to go work on one of our biggest shows of the year - the Academy Awards. We make well over a million dollars from just this one show.

Come the morning of show day, the CEO of the company is in system 5 (it was on a Sunday, my day off) and went to set up the data acquisition software to get the system ready to go, and finds there is no computer. I promptly get a phone call with lots of swearing and threats to my job. Let me tell you, I was sweating bullets.

After the phone call, I decided I needed to try and save my job. The CEO hadn't told me to do anything, but I went to work, grabbed an old Windows XP laptop that was gathering dust and installed my software on it. I then had to build the configuration file that is specific to system 5 from memory. Each meter speaks the ModBus over TCP/IP protocol, and thus each meter as a different bus id. Fortunately, I'm pretty anal about this and tend to follow a specific method of id numbering.

Once I got the configuration file done and tested the software to see if it would even run properly on Windows XP (it did!), I called the CEO back and told him I had a laptop ready to go for system 5. I drove out to Hollywood and the CFO (who was there with the CEO) had to walk about a mile out of the security zone to meet me and pick up the laptop.

I told her I put a fresh install of the data acquisition software on the laptop and it's already configured for system 5 - it *should* just work once you plug it in.

I didn't get any phone calls after dropping off the laptop, so I called the CFO once I got home and asked her if everything was working okay. She told me it worked flawlessly - it was Plug 'n Play so to speak. She even said she was impressed, she thought she'd have to call me to iron out one or two configuration issues to get it talking to the meters.

All in all, crisis averted! At work on Monday, my supervisor told me that my name was Mud that day (by the CEO), but I still work here!

Here's a picture of the inside of system 8 (similar to system 5 - same hardware)

I'm an embedded devices dev. As part of my job I take off the shelf devices and write libraries so that our JavaScript team can interface with them. If I have to deal with one more custom implementation of a standard protocol I'm going to freak the fuck out. Like fuck there are only 5 or so major communication protocols at the hardware level there is no fucking reason to reinvent some shittier protocol over a well documented, widely used protocol that has been around for 30 years. (Modbus for anyone who cares)

Building an interface for a client between industrial power quality meters and a database that serves a webapp of data.

Client had heard of a way of sending data between meter and raspberry. From some manager in a big firm.

Currently we where using modus to connect the meter to a raspberry. This method was tested and proofen to work. Both devices could talk to each other in modbus.

Client kept demaning to use mbus, and was nog listening to any reason because the firm suggested it. In the end we end up going modbus to mbus to send it to the raspberry. There the mbus was converted back modbus. Because the meter could not communicate in mbus.

Really weird experience to program something so useless. But protesting about it was going nowhere and taking more time than the changes would take to implant.

Modbus official documentation contains nice layer diagram with texts in Comic Sans?! What year is it? 2000?

Staring at computer trying to figure out why I can't read a float from modbus. I swapped the bytes correctly for my platform. I also ensured the endianess of the words matched my platform (byte endianess is not the sames as word endianess, fml). Was driving home thinking about what could be wrong. My mind saw this code:

uint32_t newint;
for(int count=0; count<2; count++){
newint |= words[count] << count;
}

Then I am fuck! It should be:
newint |= words[count] << (count*16);

This was later turned into float. I kept getting values in the 1e-40 or some shit. Now it makes sense. The upper word was not set.

This is such newb shit. Fuck you newb shit I should just know!

Reading more I realized that the endianess of words can vary between devices even though the spec calls for big endian words. Fuck you non-compliant vendors! So I gotta add a flag for fucked up devices. Fine. The pay off is a generic way to add modbus to our opcua server. I want this easily editable in the field. For now it is readonly. So that makes it nicer.

Just a little torqued that I solved this driving home instead of at work. Too close to the code. I think tomorrow I will have my boss review it to tell me of other logical crap I missed.

So I get to work on building a client at work for industrial automation. I am building a mini hmi to show customers how our server works. The code uses opcua. The reason I am making a client is because all the opcua hmis on the market are really expensive. There is nothing less than $600. There are hmis for free out there, but none of them say they support opcua. opcua has become a major protocol in the industrial automation industry.

It took me about 2 days to gin together a client that is pretty much abstracted and will be easy to maintain. A lot of that was just learning the opcua library client code.

Now I want to create servers and clients geared toward home automation for fun and profit. I want to take sensor data from arduinos using a simple serial protocol like modbus or other protocols that are supported. Then have an opcua server that collects this data. Then finally have an opcua hmi that I develop talk to these servers. The security model is much better and would be compatible with other vendors clients/servers. I already have a game engine I want to use for the hmi portion. It has tons of widgets for displaying data, graphs, lists, text, etc. It does both 2d and 3d.

This sounds like a project that could really fun, meshes with my work learning, and provides value to people that want to automate their lives.

The other side effect is that the next time I go looking for a simple and cheap hmi that supports opcua, there will be one.

How much trouble am I asking for in allowing for very large strings in attributes of json data?

I went and looked at the maximums for the string in json strings. I cannot see any real limitations. I did see if sending json data to a browser that it should not be more than 40MB. That seems excessive. I also checked my internal data types. The string can hold 2GB. Then there is a the server it will be served from in OPCUA. Which I saw discussion of strings in the 77KB range.

We are using a json file to configure what points to read from a modbus device. I am adding fields for name and notes. I could limit these fields, but part of me wants to see if some customer tries to make the world burn. For the most part we will be editing this file. But the customer may want to as well.