Just to add. The reason you actually use 4-20mA in Industrial engineering is because when we have a 4mA signal, we know it is LOW and 20mA is HIGH but if it is transmitting 0mA we would know if we have an issue with the connector or if it is broken. if LOW was 0mA, we know not know if the sensor is just transmitting an actual LOW signal or is just broken, Thats the reason it starts at 4mA.
you're right, but 0-20mA are still used. They are used in intrinsec barriere wich transmit information to control room. This scale (0-20mA) is used when high accuracy is need, but comes from a barriere who's supplyied by the main.
Very similar to my old Nexdock Touch 14", but the Nexdock has a touchscreen and 15V USB-C charging. Perfect for testing servers, mainboards, SBCs, etc. Works well with DeX too.
I spent 42 years as a boiler operator and just about everything was 4-20 ma, nice to hear someone that knows everything about them. 4-20 ma is also used for flow meters, pressure, tank level indicators, temperature, VFD controls, and encoders. Thank You Dave. 4-20 ma has been around since the 1950s.
There's also a 4-60mA standard, I think is intended for very high-noise environments like EHT and grid power systems. I only found this out when I blew up a 4-20mA optoisolator module by connecting a 4-60mA device that I didn't check the specs of.
There are quite a few different one 0 -5volt , 0 - 10v , 2 -10 volt , 4 -20ma just to name a few I'm in the HVAC industry in Australia and all the sensors use one of these values.
Minipa is a brazilian company, they are quite well known here in Brazil. These days they mostly rebrand chinese oem tools, but their products are still ok quality for the price, being factory calibrated and having all the certifications needed for it to be used by professionals here.
Package in China may meet all kind of worse scenario: Submerge in rain, throwing on and off truck, squeeze together with all kind of strange things, and finally leaving horrible logistic of China.
Back in the 90’s I used to design hardware to interface to 4-20mA signals, the interesting ones being loop powered digital indicators, I.e. they had no separate power, they consumed around 1 or 2mA and therefore the minimum 4mA signal also powered the device. Burr Brown used to have a bunch of different 4-20mA IC’s.
As someone who worked in the industrial instrumentation industry for many years, there are a couple of things regarding 4 to 20ma outputs. First, this standard has been in place for decades in the instrumentation industry used by virtually every manufacturer and until the more recent move to digital communication. And because industry does not rip out all their instrumentation and replace with the latest technology at a drop of the hat, to be compatible with the existing plant, it will be a requirement on new instrumentation products for many many years to come. Second, the missing word so far in constant. For a given parameter value generated by the instrument in the 4 to 20am current output loop, it will produce a constant current up to a maximum load. This is to cope with different length of cable plus different input load resistance on the receiving device and there can be more than one connected in series. So typically, instrument spec will say “Voltage Load if 15V or 750ohms”. So the output from the instrument will not change if the resistive values are anything between zero and 750ohms, so no current loop calibration is not necessary.
The "Look Mum, No Computer!" laptop, haha. Hell, the flex cable in that Casio game looks super cool. The whole thing can probably be restored, and I think I figured out how to play it by the look of the controls. Now, it's time for EEVBlog vs Adafruit (vs anyone else willing to participate) Giant PCB Ruler Showdown! Start your engines and may the best drag queen win... oh wait, that was a different show. The flex cable in that Casio game looks super cool, with all the shunts across it. I've never seen that done on old flex PCBs; modern double layer with vias is a different story. The whole handheld game can surely be restored, and I think I figured out how to play it by the look of the controls. I'm sure Sam Battle of LMNC could circuit-bend it into a synth, like anything he touches. Midas had his gold and Sam has his synths, haha. Nice Crustberry Pi 3, it reeeeeeeeally needs that ultrasonic bath. I've used almost all production "B" line 'berries, from model B rev 1 without the mounting holes, to the 4B and also CM4. Absolute position rotary encoder? Oh man, thing of beauty and joy for ever! Might not be the synchro of old (as seen on CuriousMarc!), but still, loveliness. Cute little flashlight, I like the retainer ring. Mechanically it seems built to last and be repairable if you don't mind that silly-cone crap, but the charger pulling shenanigans when new? C'mon... that built-in charger seems to be there for the looks, and you'll just have to do with pulling the battery out and charging it in an external charger. Thumbs down indeed for the lack of basic functionality out of the box, this is just ridiculous. One for discombobulation and the other one, you decide. Interesting transparent rulers. I'd put one on my workbench somewhere.
The Crowview thing isn't new. Nexdock used to make the Touch 14" which was actually better in some ways than the Crowview, for example it had a touch display and USB-C charging instead of a proprietary wall-wart. Those powerbanks look like they were made using spare flashlight cases, they simply replaced the flashlight bit with a powerbank board. Interesting design. Also a good way to make use of your spare 18650 or 27100 lithium cells. You should try charging the lithium cells in them with a external charger to check if they're OK, maybe they got discharged way too low and those power bank boards are refusing to charge them.
I still use my original EEVblog PCB ruler. I even used it to convince my boss to let me design a PCB ruler for our business (model rocketry). I'd certainly get another (or five) if a new version were available.
Loved the rotary encoder! The rotary hall devices have really changed how rotary sensors are designed, at least for industrial applications like I used to be involved with. Compared to other high precision devices like synchros or resolvers, the hall devices are a small fraction of the cost. You do still need good bearings and such to keep the shaft and magnet precisely located, though.
That one unidentified IC on the 4-20 encoder is probably the 4-20 driver IC, it takes signal from the DAC, and then twinkles that big transistor jobbey to get desired current on the 4-20 loop, such ICs make the design easier, more compact and a bit more robust.
When you unpluged the usb cable and the power bank was already twisted on, the power bank is in discharging mode. In that manual, when you see a green led that indicate that there is 60%-100%.
CrowView looks like my HP workstation. Is it possible it utilizes the same case and keyboard? The Casio game also styled after Darth Vader's helmet. Interesting 2-layer carbon track flex circuit. Pocket multimeter will probably clean up with white vinegar. The "0" end of the Rulerize may be better placed at the edge of the phone, so it can be used placing the edge phone against a surface.
with flashlights you need to polish the aluminum contacts on a paper towel , lots of black stuff comes off , maybe measure the battery with multi-meter too. does that circlip add an extra electrical contact surface ?
I don't believe the Wurkkos 21700 is protected. In my experience, that circuit is usually put on the negative terminal. All of the Wurkkos lights I've used have low voltage cutoff in the light itself, so I don't imagine they're bothering to bulk up their cells with protection. It's a shame your power banks seemed dodgy - Wurkkos' lights have a pretty good reputation (and the internal charging is generally fine). I wonder if these are made by a different OEM?
A magnetic rotary encoder isn't fully linear with respect to angle. When the magnet isn't exactly on axis this gets worse. I wonder if they compensate for this.
Heard lots of worrying stuff about that CrowView lapdock/kvm/console, apparently it's an old design they just rebranded for the kickstarter and the previous model had sketchy charging circuitry... Sadly the next cheapest competitor Nexdock is about double the price while having plenty of its own issues and a proper laptop style KVM from HP costs close to a grand used...
if you want to use display with usb-c, you need to use special type-c like usb c thunderbolt and can't use regular usb c from phone since they use more core cable for display communication.
Getting the angle for a one bit change is pretty straight forward with a sine bar and some gage blocks. 1/4000 of 5" is . O013 difference in the ends, easy to get an appropriate pair of stacks and a second pair for the 0:1 slope measurement. Seems a waste to send an analog signal when you could just as easily run 4-20mA serial output like an old Teletype. 1 bit of error in the analog output is only 3 μA.
4-20mA serial would be useless for industrial control, which this is clearly aimed at. A digital output version would need to be something like Modbus, CANopen or DeviceNet to be useful as an industrial sensor.
The Americans almost exclusively use binary fractions when dividing the inch. So, halves, quarters, eighths, sixteenths and so on. This ruler is marked at 1/8, which is fine for just about anything. 1/16 would probably have been a bit too busy.
Попробуй испытать этот энкодер поднеси к нему магнит сбоку и какая будет ошибка ? Возможно им нужно подумать над разработкой дополнительной версии корпуса из ферромагнитного материала.
Casio made some terrible war games in the 80s, I remember a thingy called "Heli-Battle". They are nowadays quite expensive, people collect everything..
33:56.... The Ali listing shows the USB C as a 20W Output Port and the USB A as a 20W Output and Input Port... Sorry.. I don't have the User Instructions.
could be battery is trashed, with a capacity of like 5mAh, so charges up quick, system thinks its fully charged, stop charge and it crashes below minimum immediately, should test batteries, or with other battery?
