Aram, I think what you are talking about is a torque limit, which generally translates into a current limit on a servo drive.
Internally, many or most servo drives have a current loop, then a position loop outside of the current loop, and finally a velocity loop on the outside of that. EMC2 "usually" ties into the servo drive at the velocity loop level via the the plus or minus 10 volt interface. A torque limit would usually be implemented at the drive level since the CNC system does not directly control the servo motor torque. I've implemented torque limits on brushless servo drives via a separate +/- 10 volt input to the servo drive which changed the max current that the drive could output, to implement a torque limit. I'm sure that EMC2 is flexible enough that you could implement an Mcode to output a certain analog value that could be used to limit the torque at the drive level, but it would not be anything "standard" for EMC2. Dave On 4/18/2010 3:09 PM, a...@conceptmachinery.com wrote: >> Hi Ray. >> I am thinking about CNC machine that can safe way interact with human >> (people). >> That machine must be one with which person can wrestle with without danger >> to get injure. for example massage ( CNC programmable)machine. >> That is why i want to use M80 47 code (M80 electric current overwrite, for >> 47% from maximum level). I think also need M85 code that show for how long >> overwrite - like 1 -4 minute until machine go into Alarm mode. >> >> With code M80 and M85 in place person/human can be safe way deal with CNC >> programmable machine. >> > I forgot about M90 - to program how accurate machine shout be. for example > M90 1.500 means that if machine in + /- 1.5" from target place it is OK , > and go to the next block. For massage machine accuracy +/- 1.5" will be > good enough, i think > > > >> Today many medical thing will be given to robots (CNC driven machine) and >> it will be important part of overall economy. >> >> thanks >> Aram >> >> >> >>> A servo system like you are using runs torque (amps) up or down >>> depending upon how big the difference between commanded and actual >>> position is. That delta is computed in the EMC but is implemented by >>> the motor drive. The tuning of your motor drive is a critical part of >>> what you want. >>> >>> The second part of this is related to the EMC. In the EMC and most >>> other motion control systems I've encountered you normally tune PID and >>> Feed forwards to produce the desired motor characteristics including >>> torque. After that tuning is done properly you can adjust commanded >>> position to control motor torque. But that tuning is a static or >>> constant sort of thing. Some systems watch spindle load and will change >>> tools when the load reaches a certain critical point. >>> >>> My thinking is that you'd need to add in some feed override so that you >>> get good cutting, reduce chatter, or meet a machinist's feel for the >>> cut. EMC, through HAL has adaptive feedrate control that could be >>> hooked up to say a summed or weighted average of following error for the >>> relevant axes. Such a system might do what I imagine that you are >>> asking. >>> >>> Rayh >>> >>> >>> On Sun, 2010-04-18 at 02:00 -0600, a...@conceptmachinery.com wrote: >>> >>>> Hi >>>> I want to ask about electric current that turns AC servomotor in EMC2. >>>> I think EMC2 works like that: Tool move with lowest electric current. >>>> When >>>> tool is encounter resistance from work part etc. EMC2 increase electric >>>> current to overcome that resistance. Increase electric current >>>> translates >>>> into increase of torque from AC servomotor. >>>> Can I control that electric current? >>>> How is possible to put overwrite 0% to 100% that electric current? >>>> If I set overwrite to 100% than system behaves as it is. If I set >>>> overwrite to 0% than system does not move. If I set overwrite to 10% >>>> than >>>> smallest resistance to tool will stop machine. When resistance reduced >>>> than machine move to execute next bock of code. >>>> >>>> Can it be M code (machine code)? M80 47. (etc) >>>> Means 47% electric current overwrite. >>>> >>>> Thanks >>>> Aram >>>> >>>> >>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> Download Intel® Parallel Studio Eval >>>> Try the new software tools for yourself. Speed compiling, find bugs >>>> proactively, and fine-tune applications for parallel performance. >>>> See why Intel Parallel Studio got high marks during beta. >>>> http://p.sf.net/sfu/intel-sw-dev >>>> _______________________________________________ >>>> Emc-users mailing list >>>> Emc-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>> >>> >>> ------------------------------------------------------------------------------ >>> Download Intel® Parallel Studio Eval >>> Try the new software tools for yourself. Speed compiling, find bugs >>> proactively, and fine-tune applications for parallel performance. >>> See why Intel Parallel Studio got high marks during beta. >>> http://p.sf.net/sfu/intel-sw-dev >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> >>> >> >> >> ------------------------------------------------------------------------------ >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
