Eduard Nesterov <[EMAIL PROTECTED]> wrote: > I am running emc2.0.5 with Xylotex board and Taig mini mill. Before I > adjusted SCALE_INPUT parameter I was able to run sample nc file without > problems. After I set SCALE_INPUT = 32000 (200*8*20) 0 "joint 2 > following error" keep showing up. > I started emc from the terminal and got the following error description: > emc/task/taskinf.cc 787: Error on axis 2, command number 1321 > > Could anyone help me understand what is going on.
You are asking for more steps per second than than software step generation can give you. What is your BASE_PERIOD? The default is 50000nS, or 50uS. That means the "step" signal can change no more than once every 50uS, or 20,000 times per second. Since every step pulse has a rising edge and a falling edge, you can't generate more than 10,000 steps per second with the default BASE_PERIOD. If your scale is 32,000 steps per inch, and you try to move at 0.5 inches per second, that means you need 16,000 steps per second. You won't get it, so the motors fall behind and you get a following error. The default value of BASE_PERIOD is very conservative, since making it too fast could drastically slow down or even lock up your computer. But you can probably reduce it from 50uS (50000) down to 25uS, 20uS, or maybe even less. At 20uS, you can have 25,000 steps per second. It takes very simple math to see what the limits are: First, try running EMC with smaller values for BASE_PERIDO, until you find a "good" value. "Good" means the lowest value that doesn't cause significant slowdown of the computer. Try 25000, then 20000, 16000, etc. Lower it a bit at a time, start EMC, and see if the system feels "sluggish". If the mouse starts to get jerky and windows respond slowly, raise the value a little bit. If you are a little too low, you get slow response. If you go a lot too low you can lock up your system, so go in gradual steps. Once you find a BASE_PERIOD that works, you can calculate the maxiumum step rate. It is 500000000 / BASE_PERIOD steps per second. The next step is to calculate your maximum speed in inches per second. (Or mm per second, but since your scale is 32000, I bet you are using inches.) The maximum speed in inches per second is the max step rate that you just calculated, divided by your scale. For example: Suppose you find that the lowest BASE_PERIOD you can use is 19000. Max step rate = 500000000 / 19000 = 26315. Max speed = 26315 / 32000 = 0.822 inches per second. You always need some "headroom", so in this case I would set the max speed to 0.75 inches per second, which is 45 ipm. Regards, John Kasunich ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
