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bikepete
08-12-2016, 09:06 PM
What do people recommend for drawing electrical schematics/wiring diagrams? Ideally cheap or free...

I've done it in Adobe Illustrator up to now but there's got to be a better way.

So far I've found and briefly tried TinyCAD (https://sourceforge.net/projects/tinycad/) which is open source freeware.

Any other suggestions?

A_Camera
08-12-2016, 09:46 PM
I am using Eagle. It's free, but the free version has limitations. Never the less, the limitations are pretty generous, so it can be used for board sizes up to 80x100mm. I use it also to generate PCB layout. Here is the latest thing I made with it:

https://adapting-camera.blogspot.se/2016/12/the-making-of-pulse-stretcher.html

19931

Just a simple thing this time, but it works excellently well. Eagle has a bit of a steep learning curve uphill, but once you understand it, it is very nice to use. I also have PCB123, but have not used it for a while, I think Eagle is better.

bikepete
08-12-2016, 10:06 PM
Thanks! I'll check it out. I've also just downloaded KiCAD (http://kicad-pcb.org) - seems a bit more polished than TinyCAD at first glance.

But pretty much all of them seem to be oriented around PCBs and integrated circuits. All that ('electronics') is a mystery to me, but I'm OK with basic electrical circuits.

What I mainly want to draw easily is a machine circuit diagram - with AC lines, contactors, start/stop pushbuttons, inverters, motors, inverter control wiring, that sort of thing.

I'm sure it's do-able in any of these systems, but neither of the two I've tried so far seem to have suitable component symbols built in. I probably just need to work out how to add in a suitable library...

bikepete
08-12-2016, 10:35 PM
Ah, just found an old post asking exactly the same (http://www.mycncuk.com/threads/5479-FREE-software-for-electrical-schematics) - I did search before but didn't spot it - anyway a poster there recommends QElectroTech (https://qelectrotech.org/) which seems to have been built with control/automation in mind. Off to check it out...

EDIT - and having got it going it looks ideal for me. Seems to have all the stuff I need - and looks well laid out and put together too. Off to try to draw something...

PeteL
08-12-2016, 10:51 PM
ProfiCAD seems OK - free for home use. It has a good range of symbols & components and its very easy to make your own custom symbols.

The limiting factor is that you can only use A4 sheet size and their drawing border...

bikepete
09-12-2016, 08:16 AM
Many thanks for that - downloaded it (https://www.proficad.com/download.aspx) too. Looks really good - maybe a more friendly (graphical) symbol picker than QElectroTech, but I think QElectroTech has even more symbols - including e.g. ready made blocks for Danfoss/Yaskawa/ABB inverters. Will have another go later and decide which to put time into getting familiar with...

SparkyLabs
01-01-2017, 10:15 AM
Kicad is good but I had to give up for professional work but the schematic side is OK once you work out the library nightmare. Diptrace has a free version but I'd not recommend wasting money on it.

Sent from my phone so mind the autocorrect.

Jonathan
01-01-2017, 03:15 PM
Kicad is good but I had to give up for professional work but the schematic side is OK once you work out the library nightmare. Diptrace has a free version but I'd not recommend wasting money on it...

It's not what the OP needs, but for designing PCBs I think KiCAD is worth persevering with. I have Altium on my work computer, but for me, the slight functionality it gains over KiCAD is negated by the software needing a licence to run. I also found Eagle and Diptrace easy enough to use, but again they cost money for anything serious.


I use it also to generate PCB layout. Here is the latest thing I made with it:

https://adapting-camera.blogspot.se/2016/12/the-making-of-pulse-stretcher.html


Instead of making this PCB, you surely could have used a smaller series resistor for the LED a lower value, as the issue is just the low duty cycle? LEDs are fine with pulses of higher current, so long as the output is never stuck on...

Doddy
01-01-2017, 05:35 PM
Instead of making this PCB, you surely could have used a smaller series resistor for the LED a lower value, as the issue is just the low duty cycle? LEDs are fine with pulses of higher current, so long as the output is never stuck on...

I normally read everything you write, Jonathan, with considerable interest and intent to learn; however, the above is not sound advice : Most designs would work on a IF=10-20mA with an IF(max) of 30mA or so - and so limited ability to increase the current (and therefore the emitted optical energy) within the constraints of the device; some (though by no means all) manufacture's datasheets will provide a peak IF rating given explicit constraints (e.g. 100mA at <10% duty-cycle with a pulse-width < 1ms), unless the OP is designing within the limits of the LED datasheet then exceeding the maximum rating of the device will, in all probability, reduce the reliability of the device and result in premature failure. You're also suggesting something that would cause significant current spikes on the driving system, which at reasonably high frequencies could cause EMC issues and possibly problems with the drive system. It's a design, designed to fail.

What the OP did with the pulse-stretcher is a well-engineered solution to his problem (though I'd do it differently!)

Jonathan
01-01-2017, 06:16 PM
Fair enough, I didn't think this one through - the signal should at least first be buffered (as the OP did) as we don't know the drive capabilities of the BOB and wouldn't want to adversely affect the signals to the driver optocouplers. Even so, as you say, there is a chance of the high di/dt causing issues elsewhere.

If obtaining the required brightness with any method requires operating above the LED pulse current rating constraints, then my proposal is moot. Although I would question how much the reliability matters here - after all the LEDs are just a neat accessory to the machine.