Hello all
If this is of any interest to anyone, would be very glad of help.
Sitation presented here - page on own website.
So that's Arduino + MCP9600 thermocouple amplifier + thermocouple
The "breakout board" can be seen here
Image of an Arduino
Best wishes, Rich Smith
Hello all
If this is of any interest to anyone, would be very glad of help.
Sitation presented here - page on own website.
So that's Arduino + MCP9600 thermocouple amplifier + thermocouple
The "breakout board" can be seen here
Image of an Arduino
Best wishes, Rich Smith
-------------------------------- Each I2C string begins with the address of the target, which you have to know to communicate with it. Around 2000 I wrote a program that controlled a Texas Instruments Power Over Ethernet applications board using the printer port of a computer to generate the I2C address and SDA + SCL signals, so the board and cable could plug into a customer's unmodified lab PC. A 2 channel digital storage scope with a decent amount of waveform memory should let you capture, view and analyze the command sequences. Don't ALTernate the SCL and SDA channels, their phasing is critical. You can experiment with how triggering and sweep mode work by turning a power supply on and off.
My thermocouple amplifiers have analog outputs that a PC-connected DVM can read, some can read Type K directly. I haven't played with I2C since then and don't remember the details. I understand structured programming but I'm not all that familiar with the subtleties of C.
Like the lathe and mill, you won't get far in electronics without an oscilloscope. My small portable one is a used Tenma that I took a chance on at a flea market. It's somewhat noisy but good enough for hobby use. At least one metered current-limited power supply is very useful, partly for its fault detection and protection ability. I prefer 4-1/2 digit precision on one multimeter for working on measurement circuits, otherwise 3-1/2 should be fine.
Each I2C string begins with the address of the target, which you have to know to communicate with it.
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Here's what it looks like:
"Once the first 8 bits of the frame are sent, the receiving device is given control over SDA. If the receiving device does not pull the SDA line low before the 9th clock pulse, it can be inferred that the receiving device either did not receive the data or did not know how to parse the message. [wrong address?] In that case, the exchange halts, and it's up to the controller of the system to decide how to proceed."
In the sparkfun schematic the funny looking things in brown are MOSFETs, electrically controlled on/off switches. A voltage on the unconnected (insulated) vertical bar enables current flow between the blocks, in this case shorting the signal line to ground while the resistor limits the current to a milliAmp. The diode is an unavoidable part of the structure.
Understanding data sheets was a large part of my job. Some of it was confirming that the device really did what the sheet said it would.
Thanks very very much for that. Found MCP960X-Data-Sheet-20005426.pdf and suspected it had value. Now I know "it's it" I will spend time on it over time.
This is all so new to me. Before yesterday morning I didn't know of "pull-up resistors", for example. I altered a circuit to test this
Better try to get back to sleep for now. Thanks. Rich S.
Also the address codes and lengths have to match. It's apparently 8 bits for the MCP9600, with the least significant bit ignored.
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Correction, the address is 7 bits, with the first being the constant 1100 pattern. The 8th bit is 0 to command a Write, 1 to request a Read.
Cheer up, at least it's in (technical) English which I can translate. I figured out how to decode the output of a meter that serially transmits the display's LCD segment pattern by studying a program written in German.
Isn't electronics fun?
I saw that PDF earlier but didn't feel I could add anything to help at the time. I recently did my first serious Arduino project doing a bit of motor control with a Nano and using a counter to produce a periodic 4Hz interrupt. I found some of the online tutorials vague and talking about counter compare and counter overflow in the same article and not clear about what examples were for but sorted it in the end after looking more into the various register set-ups. Interrupts as well from rotary encoder on digital 2 input. 30+ years of C coding in various environments meant I was aware of issues with interrupts and the need for certain variables to be declared 'volatile' and handled accordingly.
Make sure your IDE is up to date as mine wasn't and I had and issue with 'digitalPinToInterrupt' not being recognised so removed that IDE and installed the latest and all good.
A classic MC68000 text mentioned some problems are best solved by leaving them and having a beer and getting back to them the next day or something like that, it definitely works for me pondering on a conundrum.
The "breakout board" can be seen here
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I didn't see a schematic and the MCP9600 has no INT pin, maybe it's an Interrupt that can be connected to one of the Alarm pins to trigger the controller to immediate action, like shutting off a heater.
An Interrupt is a hardware input that immediately jumps the program counter to a specific location, to run (or redirect to) a routine that handles whatever triggered it. The alternative is sequentially checking the inputs and is usually fast enough, and simpler.
For US Type K thermocouples, red is (-) and yellow is (+).
"Second picture is where commented-out "pinMode(2, INPUT_PULLUP);". Initially LED lighting randomly when button not pressed. Then added in the circuit the "pull-up" resistor connected to on-board supply voltage and the circuit behaved like the first circuit."
Unconnected inputs are sensitive antennas that pick up secret messages from space, or noise from fluorescent lights and radio/TV transmitters. Some even float to a middle level where they partly turn on both the input high and input low circuits, causing oscillation or higher power consumption. They are all best made high or low if not used. When you have an oscilloscope touch the probe to your finger and see how much electric noise you carry around.
The traditional initiation rite into electronics is releasing the magic smoke. Hopefully it's one-time, like forgetting to lower your helmet
Yes... ... ... And also what these days do to you - well certainly to me. If you can relate to it - that was the point I was at - "you've grubbed-around, have seen some of the concepts and learned some of the words - now look up and outwards and step clear because you cannot do this to yourself".
I had some cider and watched some abandoned mine exploring videos. Crazy that people do this. Must find a network and try it :-) One which must be very near where I live had them wading through the ochre stuff with reddish liquid looking like what gave the Rio Tinto its name - if so the extremely acidic stuff. In vast mined-out galleries (normally "our" lodes are narrow, nearly vertical and oriented SW<=>NE). Looked to be sulphide ore area (?) -> (?) there were "stalagtites" of what looked like the iron-y arsenopyrites we get in the copper-mining areas (?) around here.
I know of the demonstrable proof that electric circuits run on smoke, and the smoke must be retained just like a boiler holds steam.
It is a bit of a thought that I would need an oscilloscope to proceed much further. I have seen videos of them used to diagnose even what is happening when you push a push-button - all sorts of noise! With the oscilloscope showing very clearly.
"Compensating cable" - can only handle "room temperatures" but has same thermo-whatever response to temperature in that range and is much cheaper than the "real" thermocouple alloy.
"Richard Smith" wrote in message news: snipped-for-privacy@void.com...
It is a bit of a thought that I would need an oscilloscope to proceed much further. I have seen videos of them used to diagnose even what is happening when you push a push-button - all sorts of noise! With the oscilloscope showing very clearly.
------------------------------------ You don't absolutely require a digital storage scope unless you -must- solve the problems you encounter, I've given you some hints, another below. They are less expensive than a lathe or milling machine or electric welder of useful size and won't keep hitting you up for accessories and consumables as those will, except perhaps a non-contact current probe for motor starting current. As an example the specs on this look adequate for troubleshooting I2C waveforms.
The tag on that MCP photo gives the I2C address as 66 or 67. Those are hexadecimal numbers, base 16 instead of 10, that handily represent blocks of
4 bits in more human readable form. 66 is 110 0110. The bit weights are 8 4 2 1 and the hex value is the sum of those that are 1, 4 + 2. A-F represent 10-15. Sometimes they are prefixed with 0x or such to indicate hex instead of decimal.I find the test equipment available nowadays truly amazing and especially at that price... However my old stuff from ~30 years ago still works (some pots and switches could use cleaning) and I wonder how long these new items will last. Of course if they were to work for another 20 years I'll not likely be around to complain about it😉
It is a bit of a thought that I would need an oscilloscope to proceed much further. I have seen videos of them used to diagnose even what is happening when you push a push-button - all sorts of noise! With the oscilloscope showing very clearly.
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Yes, the simple-seeming things aren't when you look closely. That's why design engineers who learned the book theory need technicians who know the grubby practical aspects. In that instance the initial contact is a signal to wait 10mSec or so and check again. Fingers generally can't press and release a button in less than 50mS.
In my original field the student is expected to learn and practice both. I learned basic glass-blowing (tee joints) and the polishing and etching of metal samples to examine the microscopic crystal structure.
I suggest you not be tempted by less than a 2 channel digital storage scope. The older stuff is good for following an audio or video signal to measure its changing amplitude, without having to decode it. Digital scopes record much more than the screen width shows and can scroll through, expand or compress it later. They are better than a datalogger for rapidly changing signals like pulsed welding current and motor starting surges, perhaps even the response of a strain gage as the sample breaks.
I find the test equipment available nowadays truly amazing and especially at that price... However my old stuff from ~30 years ago still works (some pots and switches could use cleaning) and I wonder how long these new items will last. Of course if they were to work for another 20 years I'll not likely be around to complain about it😉
I picked up (Ebay) a Fluke 8010A and a 37 a few years ago. Was hoping for the best but they both need work. Would really like to get the 37 working. It's a lot like my 87 but not quite the same spec. Has a bargraph display which can be handy when tuning circuits. Made to sit on a bench or portable. Uses a 9v battery, same as 87 series. Suspect the input protection, "Varistors" maybe flakey. I ordered some in but have been too lazy to seriously dig into it🤷 The 8010A may need some serious switch work/cleaning. Used to see those switches in radio equipment and they were prone for dirt/noise. Royal pain to desolder and probably unobtanium to replace nowadays. So need to be carefully disassembled and cleaned...
I don't lack for projects just the drive to do it😑
I picked up (Ebay) a Fluke 8010A and a 37 a few years ago. Was hoping for the best but they both need work. Would really like to get the 37 working. It's a lot like my 87 but not quite the same spec. Has a bargraph display which can be handy when tuning circuits. Made to sit on a bench or portable. Uses a 9v battery, same as 87 series. Suspect the input protection, "Varistors" maybe flakey. I ordered some in but have been too lazy to seriously dig into it🤷 The 8010A may need some serious switch work/cleaning. Used to see those switches in radio equipment and they were prone for dirt/noise. Royal pain to desolder and probably unobtanium to replace nowadays. So need to be carefully disassembled and cleaned...
I don't lack for projects just the drive to do it😑 Leon Fisk
----------------------- I have a Fluke 8060A DMM whose self-test (REL while power-on) reports bad switches, though sometimes it works after spray cleaning. I don't dare touch those switches with an iron.
Never used one of those but I saw them in other techs kits now and then.
Per manual here:
Really tedious but you could pull the retaining clips off the inner plastic plunger and carefully pull them out along with the metal contact strips. Use an eraser on those strips and similar on the standing pins inside the shell they contacted with. Some silicone grease used sparingly on the interlock bars...
Really tedious but you could pull the retaining clips off the inner plastic plunger and carefully pull them out along with the metal contact strips. Use an eraser on those strips and similar on the standing pins inside the shell they contacted with. Some silicone grease used sparingly on the interlock bars...
Leon Fisk
------------------------------ Thanks. I was taught to use an ink eraser to clean contacts. The Army tool kits for telephone and Teletype repairmen included contact burnishers. The school concentrated on electronics, ciphony and Modems, and slighted the mechanical components.
I was using "burnish" in a general sense. It's really hard to get anything inside those switch shells to clean up the contact area. So maybe a Q-tip with something on it, bit of cloth held in a hemostat... you have to improvise with something depending on how bad they look to be🤷
I have several different erasers, they work pretty good if they can reach the problem area🙂
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