Andy, I looked over the information you provided. It is not clear to me how the 7i80hv_16_sv.. "SV" sections work. The card provides a PWM output for the 7i40, the encoder feedback comes back to the 7i40 and then back to LinuxCNC servo thread where the loop is closed? So is this then just a single control loop instead of the typical nested Position and Velocity loops that one would have with a velocity mode drive using velocity feedback to the drive and position feedback for LinuxCNCs position loop?
Regards, John Figie On Tue, Nov 24, 2020 at 5:07 PM andy pugh <bodge...@gmail.com> wrote: > On Tue, 24 Nov 2020 at 20:25, John Figie <zephyr9...@gmail.com> wrote: > > > I am thinking that I want to use Mesa Etherent I/O cards and I want to > use > > PID servo control. > > > > About the motors: These are Peerless DC motors (8 brushes). 66V max and > > 3.75 Amps Max. 800 RPM coupled directly to the ball screws with a servo > > coupling. > > Mesa have a suitable dual-motor servo drive, the 7i40HV: > > http://store.mesanet.com/index.php?route=product/product&path=83_90&product_id=147 > > That pretty-much puts you in the 50-pin-header section of the Mesa > catalogue, so as the main FPGA card your choices (using Ethernet) are > 7i93 (headers for two cards) or 7i80HD (headers for 3 cards, and > available with two different FPGA sizes) > > http://store.mesanet.com/index.php?route=product/product&path=83_85&product_id=341 > > http://store.mesanet.com/index.php?route=product/product&path=83_85&product_id=62 > > The 7i40 includes an interface for incremental encoders, so you would > probably just need to choose a generic IO board such as the 7i37TA to > complete the system. > (Or you could go with a 7i44 and a bunch of smart-serial peripherals) > > The 7i40 manual is not linked from the product page (something of an > oversight, PCW) but is here: > http://www.mesanet.com/pdf/motion/7i40man.pdf > > The 7i40 will work with any firmware with "SV" in the bitfile name, so > despite the fact that it is not mentioned in the 7i40 manual, the > 7i80HD with the 7i80hd_16_sv12 would be able to drive up to 12 motors > via 6x7i40 cards. > In practice you would "turn off" the other potential "SV" sections to > use the pins as GPIO for the other cards. > > It looks like you can probably use the 7i80HD-16 unless you need to > use a 7i49 card to read resolvers. > Which begs the question, what was the feedback method used when the > lathe was new? > > Similarly the 7i93 appears to have SV and SVRM (servo/resolver) > bitfiles available so should work. > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
