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Forum Index : Microcontroller and PC projects : Pi Pico Serial Question
| Author | Message | ||||
Zonker Guru  Joined: 18/08/2012 Location: United StatesPosts: 761 |
Good morning... I have a project for work coming up that involves monitoring lots of SuperCap modules from Eaton. I need to know if the Pico supports the Enable pin of a Rs-485 transceiver IC as this is how I was going to connect all the sensor boards up and talk back to a bigger touch panel board. I don't see any mention of it in the manual, but, maybe I just missed it somehow... I could always use any of the Microchip variants as a plan B... Thanks for any feedback..!!  |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6787 |
No, it doesn't. If you want Enable on RS-485 you have to use a normal GP pin and control it yourself. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 858 |
No need to waste a pin |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Auto direction control..?? Neat... Thanks for the info...  |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6787 |
Only use those if you can get them. :) I usually get hit by stupid postal charges unless I'm buying a lot of stuff. Sometimes a pin and a couple of extra lines of software can save a lot of cash. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
I have ordered 25 of the SOIC parts from Digikey... I will try to get a prototype setup going, passing data from the sensor Pico module to the main GUI touchscreen status Pico and come up with some kind of Tx/Rx serial protocol... I want to first just monitor the Over voltage output of the Supercap module and then attach a "one-wire" based temp sensor to mount inside... I am doing this as a "homework" task and will show the results to the manager of the testing department... eaton-xlm-supercapacitor-module-instruction-manual-with-temperature-control.pdf Edit - Forgot to mention... The supercaps are replacing many 12v lead-acid "overnight" batteries.. The size of the room in power is 2 megawatts... Can be setup as switchable voltages ranging from 200v to 1000v... Let's say that there will be quite a few cupercap modules in the overall system...  Edited 2024-01-16 11:31 by Zonker |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 858 |
That is some serious wattage. Are you allowed to take pics? I have been looking at supercaps recently...pretty darned cool  |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 858 |
 "Hey, when you see our intern, just have him stick this piece of wire across those terminals" |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6787 |
Those are beautifully scary. :) A good idea to be able to keep a check on the temperatures without going near the place! Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9115 |
I've just looked at the datasheet for these modules. Am I missing something? 130F at 62.1V for £2,305.99 from digikey That gives an energy storage of 250667 joules = 0.069629722 kilowatt-hours. Compare that to one of my RC batteries (£60 from China) 22.2V 5000MaH = 22.2 * 5000 * 3.6 = 399600 joules = 0.11 kilowatt-hours So double the capacity for less than 3% of the cost. Now admittedly my battery will only discharge at 250A continuous and does have a more limited life but still....... |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
The main reason for the switch is the way the testing department needs to run the final machine "QSO" testing... normal lead-acid batteries don't like repeated charging at 100 to 500 times the typical C rates for the chemistry.. So, supercaps allow for this high current charge/discharge testing sequence.. Some of the machines we have for "life cycle chemistry testing" made for the car industry "pack" work have 2 DC output ports, each capable of hundreds of amps up to 1000v... They have 600kw bi-directional AC inverters supplying a DC "link bus" to the computer controlled DC/DC output inverter sections... The machine I just finished up testing was an "end if line" discharge tester that is made for 12v batteries and handles 1500 amps... There are several in the "mid voltage/amp range and lower voltage "single cell" testing as well... I will try to sneak some pictures out as things progress...  Edit: I did manage to snap some as the truck was loading up the dead batteries... There were 2 piles like this... Yep... A lot of "dead lead"... BattPix.zip Edited 2024-01-17 12:10 by Zonker |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Good evening folks... I finally got a chance to get some THVD 1406 Rs-485 transceiver IC's and tried doing some simple serial transmit scope shots...  The upper blue trace is the Tx output and the yellow is the A output and is unloaded but in phase... After some testing, I noticed you have to run the baud rate at 460800 or higher or the transmitter section will time out and corrupt the bit stream... Will be testing 2 way communication during the week... Edited 2024-01-29 10:21 by Zonker |
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| zeitfest Guru Joined: 31/07/2019 Location: AustraliaPosts: 482 |
I thought supercaps had degradation issues if they are kept in a charged state long-term ? |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Most of the testing will be done with the caps not being allowed to hold the charge state after testing is completed for safety reasons... An advantage over regular lead-acid batteries.. A micro controller will have control of a 50 ohm discharge resistor to relax the cap when testing is completed... The micro will also monitor the OV detector and we will be measuring the cell temps as well if the testing parameters get out of hand... Also talk of having a lower resistance in parallel with each module that can be selected as well... Most of the tests will be using constant current CHG/DCH parameters and hence produce a triangle type of voltage reading during test cycling... It is thought that adding the "shading" resistor will make it easier to see the peak power point of the test when printed in graph form... (head scratching continues)... |
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| pwillard Senior Member  Joined: 07/06/2022 Location: United StatesPosts: 292 |
I did a post about it ages ago... in case you don't have the new chips. http://pwillard.com/?tag=rs485 |
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