On Wed, 4 Apr 2018 12:57:03 -0700 "John Dammeyer" <jo...@autoartisans.com> wrote:
> In the past ESTOP appeared to be pretty simple a 12V or 24V control signal > was routed through any number of Normally Closed (NC) switches and then run > into relays and or opto-isolated inputs. Any ESTOP even would then interrupt > the control voltage and relays would open dropping all power. > > However things have changed a bit. With PCs in the mix, rules changed and > PCs and control systems could stay active but anything in hardware dangerous > to humans was now switched off by the signal interruption. > > Enter a wide variety of motor controllers. The HP_UHU has an active low > ESTOP IN/OUT signal. A low on the ESTOP input shuts off power to the drive > control logic. If the drive has a fault, it brings this line low too and > any other HP_UHU drives are also then pulled into ESTOP mode. I think this > would be better identified as ENABLE rather than ESTOP. > > The STMBL AC Servo drive I'm currently working with has an ENABLE high input. > So when Low it's disabled and stepping pulses can't move the motor. Then working with frequency inverters I come upon the term "safe torque off" and are pretty sure there are special requirements on this signal. I think this particularly apply to DC motors since failure mode close may cause it to run at full speed. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
