Alex Joni wrote: > Hello, > > Pete brings up an interesting point. > Is it allowed to issue some MDI commands while in e-stop reset or even > e-stop mode? > AXIS (the GUI) simply disables MDI while machine is not switched on. > TkEMC relies on task to do the "right" thing, and enables MDI and allows > users to send MDI commands, and task then discards the ones that are not > allowed. > > What do you (CNC users ;) think should be the reasonable thing to do while > the machine is not switched on? > > I can see valid reasons to do both approaches: some M-commands might be > usefull while in E-stop .. to make some clampings move, activate things, > etc. > Otoh one might argue that while e-stop nothing is allowed to move/change. > > Awaiting your input. > > Regards, > Alex
If I were building the machine, ANYTHING that could possibly hurt someone would be disabled IN HARDWARE when the machine is in estop. "Anything" includes clamps - getting caught in a hydraulically or pneumatically actuated vise could ruin your day. Ultimately the machine builder needs to make these decisions. For example, you could have a machine where opening the guards disables all spindle and axis motion, but does NOT disable the vise, because the operator is opening the guards specifically to change the part, and he needs to actuate the vise. Another example is visible on the Mazak at the CNC workshop. There is a manual tool-unclamp button that allows you to reach in, grab the tool, push the button, and remove the tool, then insert another tool into the spindle, push again, and the machine grabs it. That clamp is released by the machine hydraulics, and when the machine is in estop, it won't unclamp - estop stops the hydraulic pump. So you can't be in estop when you do such a toolchange. However, you want to be darned sure the spindle isn't going to start spinning while you are holding the tool. Things like the above imply the existance of intermediate states between "estopped" and "machine on", each state with its own set of rules and interlocks. Depending on the level of fail-safe required, ClassicLadder may or may not be suitable for such logic. Some logic probably requires good old-fashioned electromechanical relays. Since the logic is different for every machine, it would be unwise (and probably less reliable) to embed it in EMC itself. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
