On Tue, 6 Sep 2022, John Dammeyer wrote:
Date: Tue, 6 Sep 2022 18:25:11 -0700 From: John Dammeyer <jo...@autoartisans.com> Reply-To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> To: "'Enhanced Machine Controller (EMC)'" <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] Acorn CNCHi Ralph, The reason I ask is the replies are often like yours with an incorrect assessment of features. https://www.centroidcnc.com/centroid_diy/images/centroid_acorn_cnc_controller.pdf I think 8 inputs is quite different from the 3 home inputs you mentioned. A quadrature encoder input for spindle feedback and therefore tapping is another 3 inputs and apparently on the DB-9 is also the ability in addition to 0-10V spindle speed the CW/CCW direction capability. And I count 8 relay outputs and 4 motor channels, not 3. Bari has mentioned about costs. He's right about that. The Mesa 7i95 with Ethernet connection to the PC and a choice of user interfaces with or without touch screen. Cost is $295 compared to by the time you add some relays and a power supply the cost is probably more for the Linux System. But, and it's a gigantic huge but, the response is often "I don't want to learn another OS and have to figure out what to do with Linux". Assuming then that the end user installs limits and shares a home with one on each axis he's got 6 inputs tied up. Adds a touch sensor which can share a tool height sensor input. Maybe also a small rotary table with a stepper for that 4th axis. A relay output for coolant control which is an extra cost for the LinuxCNC system. And VFD on the spindle along with an encoder. So far we haven't exceeded the I/O on either system. Costs are somewhat comparable. However, after that introductory carrot, the price for the Acorn jumps by another $159 for the "Mill Pro" which now lets you use that rotary table and do Rigid tapping. So now the Acorn is well above the price of the LinuxCNC system. We'll ignore the price of the PC for now since both are required (along with motors, belts, pulleys, limit switches etc.). If you go out and buy a laptop it probably comes with Windows 10. Finding an inexpensive laptop with hard wire (verses WiFi) internet connection is getting harder. Not sure about the touch screen side of things. Either laptop or a monitor. So price wise, MESA $295 plus some relays and a power supply so say $400. The Acorn $329+ $159= $488. So Acorn more expensive but turnkey compared to trying to install LinuxCNC on a new piece of hardware, trying to figure out what a HAL and INI file do, which user interface to install and so on... The question still stands. For that simple 3 axis + rotary table mill why buy LinuxCNC? We're not adding a tool changer or power drawbar because it's a hobby system or used occasionally in a small shop to make 5 of something. There are user groups for both types of systems. For that matter cost wise there's also MACH4 with the Ethernet SmoothStepper or a few other similar interfaces. Cost wise also in the $400 range. So why LinuxCNC? John
A 7I96S is a much closer match to an Acorn (and has more basic I/O and more expandability) for $149
A 7I95 allows 6 axis of encoder feedback (not something the Acorn can do)
Peter Wallace Mesa Electronics _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
