> > From: Rudy du Preez <r...@asmsa.co.za> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Analogue servo driving with Mesa 7i33 > > > > I have managed pretty well converting 3 machines to EMC2 - two using the > > parallel port and one using Mesa 5i20 and 7i29 cards. However, now I am > > looking at using a 5i20+7i33 setup to drive analogue servo drivers that > need > > two inputs, AN+ and AN- 10V (and GND?). It is not clear to me how this > is to > > be done. > > > > The 7i33 card has one AOUTn pin for each of 4 channels (called AOUT0 to > > AOUT4), and a lot of GND pins. How do I connect my servo driver to these > > pins?. Should the voltage on the AOUTn pin swing from -10V to +10V? > > > Normally you would connect the AOUTn pin to your drives AN+ and the > adjacent > ground to your drives AN-. Drives are wired this way (the drives have a > differential input) so that common mode noise is rejected. > > The voltage on the AOUTn pins swings from -10V to +10V > > > > > The HAL configuration talks about PWM and PID, etc. With PWM you have > PWM > > and DIR signals and with PID you have UP and DOWN. Which of these are to > be > > used and what do they mean? I think PWM can be swung from -1 to +1 to > create > >> From -10V to +10V - how does DIR fit in. What does UP and DOWN do? (UP > 0 to > > 10V and down 0 to -10V?). > > Yes, you can also use the scale parameter if you wish the command to have > a > different range, for example if you set scale to 10, a PWMGEN command of - > 10 > to +10 will generate a -10 to +10 voltage on the output. > > DIR is handled automatically by the driver > > For the 7I33 the optimum PWMGEN setting is PDM with 6 MHz rate (pwmgen > output-type = 3 and pdm_frequency = 6000000 ) > > Not sure what you mean with PID, PID has no UP/DOWN pins > > HostMot2s PWMGEN has other output modes, for example the UP/DOWN mode. but > the > 7I33 hardware uses PWM/DIR or PDM/DIR modes only (output-mode 1 or 3) > > Peter Wallace > Mesa Electronics
Thanks Peter. I am sorry, I maint PMD, not PID in my statements above. I tried to calibrate running HAL, but the analogue output is being clipped at 1 V. There is probably a setting such as MAX_OUTPUT that I have not set yet. The OUTPUT_SCALE and OUTPUT_OFFSET settings in the .ini file is also probably not correct. I don't know yet how to set these in HAL (not running EMC2). When starting up the motor is running slowly, so an offset seems required. The scaling and OFFSET as explained in the Integrator manual (p 35) is still unclear to me. In one paragraph it speaks of voltages and in another of mm/s. I will try to figure it out in the next few evenings. My impression is that a 100% duty cycle for pwmgen should give 10V out from the 7i33, but clipping is being done in EMC2 (in units I still have to find out), so the input scaling has to be right Rudy __________ Information from ESET Smart Security, version of virus signature database 4986 (20100330) __________ The message was checked by ESET Smart Security. http://www.eset.com ------------------------------------------------------------------------------ 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
