CNCzone.com-The Largest Machinist Community on the net!



Home Page Mark Forums Read Today's Posts My Replies Classifieds Reviews Photo Gallery Web Links Share Files Advertise With Us Ad List
Go Back   CNCzone.com-The Largest Machinist Community on the net! > Electronics > Gecko Drives


Gecko Drives Discuss all Gecko drives here and get direct support!


This forum is sponsored by:

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1  
Old 03-06-2009, 06:49 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road
G380 Sneak Peek

The G380 board gerbers went out for fast-turn prototype boards. I generated a rendering of what the finished drive will look like using those boards. It looked cool so I thought I'd share the picture.

Mariss
Attached Thumbnails
Click image for larger version

Name:	G380_3D.jpg‎
Views:	336
Size:	139.2 KB
ID:	77025  
Reply With Quote

  #2   Ban this user!
Old 03-15-2009, 08:31 PM
guru_florida's Avatar  
Join Date: Nov 2007
Location: United States
Age: 36
Posts: 257
guru_florida is on a distinguished road

I'm curious. What EDA software do you use? I'm going to take a guess at Altium DXP?
Reply With Quote

  #3   Ban this user!
Old 03-15-2009, 09:19 PM
 
Join Date: Jul 2003
Location: california
Posts: 525
the4thseal is on a distinguished road

so when do you think we can get this?
Reply With Quote

  #4  
Old 03-15-2009, 09:48 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road

Considering the CPLD is a Xylinx CoolRunnerII I'm using Xylinx's ISE development software. For everything else I use ACAD2000 (schematics, board layout, 3D modeling, etc.).

Mariss



Originally Posted by guru_florida View Post
I'm curious. What EDA software do you use? I'm going to take a guess at Altium DXP?
Reply With Quote

  #5   Ban this user!
Old 03-17-2009, 10:53 PM
 
Join Date: Dec 2004
Location: usa
Posts: 1,665
TOTALLYRC is on a distinguished road
Looking good.

It looks like another winner from the stable of Gecko drive.

At one point, IIRC, you were considering offering an analog version of this drive.
If so, would it be sooner rather than later and can the drive be set to no pid since the pid is done in my dspmc/ip controller. I don't know if having pid inside pid would pose any problems.

Mike
__________________
Warning: DIY CNC may cause extreme hair loss due to you pulling your hair out.
Reply With Quote

Sponsored Links
  #6  
Old 03-19-2009, 01:10 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road

Here is a scope picture of how the G380 reacts to an encoder failure or disconnect. The motor is turning at 3,000 RPM when the encoder CH_A (yellow trace) is disconnected.

The motor is dynamically braked at the CURRENT LIMIT set value, 12A in this case (green trace). Note the 'flat' current at 12A. The motor brakes to a stop 0.08 seconds later. The G380 FAULT LED lights immediately on encoder disconnect and stays lit until the encoder connection is restored.

Mariss
Attached Thumbnails
Click image for larger version

Name:	ENCODER FAIL.gif‎
Views:	88
Size:	17.0 KB
ID:	78008  
Reply With Quote

  #7   Ban this user!
Old 03-19-2009, 01:52 PM
 
Join Date: Dec 2004
Location: usa
Posts: 1,665
TOTALLYRC is on a distinguished road
Nice to see encoder detection being implemented.

What happens at very slow speed or at rest and the encoder is either disconnected or dies?

I know that perfect encoder failure detection not that easy, but it is nice too see that you are working on it. It also doesn't hurt to dream.

Mike
__________________
Warning: DIY CNC may cause extreme hair loss due to you pulling your hair out.
Reply With Quote

  #8   Ban this user!
Old 03-19-2009, 02:06 PM
fatal-exception's Avatar  
Join Date: Mar 2006
Location: Canada
Age: 37
Posts: 465
fatal-exception is on a distinguished road

Just a suggestion, and I'm probably not the only one who thinks this, but why do you use such small terminal blocks? They are a PITA to work with 'in the real world'.

I doubt size of the unit is a big consideration for most people who buy your products.

Just my opinion.

Paul
Reply With Quote

  #9  
Old 03-19-2009, 02:23 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road

The encoder fail detect senses illegal voltages on the encoder inputs (1V > illegal > 3V) using window comparators on both encoder channels. This is both a static as well as dynamic measurement so it applies from zero to any RPM. The reaction time is nearly instantaneous (< 2uS) so there is no delay from fault to shutdown.

The comparator levels are set to the minimum acceptable encoder input voltages. The secondary advantage of the circuit is it will reject sub-standard encoders from the get-go instead of allowing them to operate and produce faulty results.

Mariss
Reply With Quote

  #10   Ban this user!
Old 03-19-2009, 02:26 PM
 
Join Date: Oct 2005
Location: US
Posts: 1,220
MrWild is on a distinguished road

The terminals are fine with the right screwdriver. I'm curious how the drive knows how much reverse current to give in order to stop the motor. Does it sense back emf? How can it do that while the drive is pumping juice to the motor?
Reply With Quote

Sponsored Links
  #11  
Old 03-19-2009, 02:28 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road

Paul,

Size has an effect on price. Printed circuit boards price-out by the square inch, metal by the pound, inventory stock by the cubic foot and shipping by weight. The connector is the single most expensive item in the drive; larger means even more expensive.

Mariss
Reply With Quote

  #12  
Old 03-19-2009, 02:43 PM
Gold Member
 
Join Date: Mar 2003
Location: United States
Posts: 2,717
Mariss Freimanis is on a distinguished road

MrWild,

Any error (following error, encoder fail, short-circuit, over-temperature, under-voltage, disable input, etc.) results in the motor leads being shorted together by the bottom pair of power MOSFETs. This 'shorting' (called dynamic braking) causes the motor to act as a generator and quickly dissipate kinetic energy. Motor current still passes through the current sense resistors and the current limit circuit (set by the LIMIT trimpot) regulates the current to not exceed that value. This refinement has the added benefit of controlling motor current during a hard-stop (running into a brick wall) and preventing over-current failure of the drive.

Mariss
Reply With Quote

Reply




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What happened with the G380? davo727 Gecko Drives 22 04-17-2009 06:32 PM
SNEAK PEAK: CNC Fusion X3 Deluxe kit wisp Product Announcements & Manufacturer News 17 03-09-2009 11:01 PM
A sneak peek at the competition Death Adder Coding 6 07-18-2006 09:54 AM
Sneak preview of a new screen for Mach3 ynneb Screen Layouts, Post Processors & Misc 27 04-03-2006 05:04 PM
LetterCam Sneak Peak WarrenW General CAM Discussion 14 02-24-2006 02:17 PM




All times are GMT -5. The time now is 02:02 AM.





Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2012, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO
Template-Modifications by TMS

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361