Search found 9 matches

by beefy
Tue Mar 18, 2014 2:24 pm
Forum: Arduino
Topic: Is my bootloaded AVR really bootloaded ?
Replies: 2
Views: 367

Re: Is my bootloaded AVR really bootloaded ?

Thanks Mee_n_Mac, I would have thought the vendor would clearly state if the bootloader was for 8Mhz. My Google searches led me to some buyers experiences where supposedly bootloaded AVRs actually had no bootloader. I wonder if I had that problem. I ended up burning the bootloader myself using my Un...
by beefy
Mon Mar 17, 2014 11:17 pm
Forum: Arduino
Topic: Is my bootloaded AVR really bootloaded ?
Replies: 2
Views: 367

Is my bootloaded AVR really bootloaded ?

I have a working Uno clone board. I bought a couple of bootloaded ATMEGA328P-PU chips (Optiboot) and tried them in my Uno board. When I tried to download a sketch to them the TX led blinked faintly, that's it, and I got the typical stk500 synchronisation message. Put the original chip back in and ev...
by beefy
Sat Feb 08, 2014 4:56 pm
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Re: Short duration data logging

Thanks Waltr, I emailed the maker of my cnc electronics. They said after lots of experience they decided to have complete isolation from the arc voltage. Their circuit is proprietary so they won't give me any real details. I'm going to go with an isolation amplifier fed from the middle of a voltage ...
by beefy
Sat Feb 08, 2014 1:59 am
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Re: Short duration data logging

Thanks very much Jremington, the voltage is DC, but I was completely ignorant about the radio frequency radiation. My ISO122P isolation amplifiers are starting to look like the way to go. My cnc electronics is directly interfaced to the HV connections with a dedicated PCB. I might remove that and se...
by beefy
Fri Feb 07, 2014 5:13 pm
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Re: Short duration data logging

Do not use a common ground in this situation. The Arduino MUST be entirely optically isolated from the arc circuitry, with kV of isolation. Seems quite a few others have used this technique (common ground). Could you give reasons why you think the Arduino MUST be completely isolated. I will learn n...
by beefy
Fri Feb 07, 2014 10:28 am
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Re: Short duration data logging

Thanks Waltr,

I've got a couple of ISO122P isolation amplifiers, so I might try and use one of those. The "spiky" signal did have me wondering so maybe the isolation amplifier will help with that too.

Keith.
by beefy
Thu Feb 06, 2014 11:44 pm
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Re: Short duration data logging

Thanks Mee_n_Mac, I was starting to give up on this forum, it took 2 days just for my post to get here. Is that normal. A sampling rate of at least 1Khz (1000 samples / sec) should be OK. With 2Kbytes of ram (minus of course what might be used in the sketch) that should give me plenty storage space ...
by beefy
Tue Feb 04, 2014 4:58 pm
Forum: PIC Microcontrollers - Software and Hardware
Topic: How to Ask Questions the Smart Way
Replies: 5
Views: 868633

Re: How to Ask Questions the Smart Way

Just had a brief glance at it and one point is about members doing some homework before asking a question. I'm a member of a cnc forum and my interest is cnc plasma profile cutting of steel. I've became a lot less responsive to those who just ask other members to do something for them. This is mainl...
by beefy
Tue Feb 04, 2014 4:42 pm
Forum: Arduino
Topic: Short duration data logging
Replies: 10
Views: 1218

Short duration data logging

Hello Guys, I'm a bit of a beginner to the Arduino so if I'm talking backwards at any point, feel free to be direct with me. I've got a plasma cutter for cutting steel plate. To establish the arc, the following happens: 1). A dry relay contact closes and tells the machine to cut. 2). The air solenoi...