It also makes it very easy to connect multiple E-Stop and motion safety switches by stringing them all together in series. Any one that's pushed or hit opens the circuit and the machine stops. It's more complex to use normally open stop/safety switches because every one has to be wired in parallel with all the wires connecting together somewhere or two complete parallel lines of wire have to be run around to all the switches.
On Wednesday, April 20, 2022, 10:29:42 AM MDT, John Dammeyer <jo...@autoartisans.com> wrote: Ask yourself this question. If a wire connecting to the limit switch or ESTOP breaks or becomes intermittent does the system safely stop? One of the biggest reasons for using NC type switches (or PNP) is that a failure in the power or wiring to them also causes a stop. John > -----Original Message----- > From: Leonardo Marsaglia [mailto:ldmarsag...@gmail.com] > Sent: April-20-22 8:55 AM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] NPN inductive sensors on 7i70 board > > Hi guys, > > A quick question to see if there's anything wrong with this. > > 7i70 comes ready for PNP sensors. In the mazak all the sensors were NPN so > when we converted it to LCNC we had to add a resistor between the +24 volts > and the input of each sensor on the 7i70 to have the two states and avoid > replacing all the sensors. We used the inverted pins in HAL so it's all > working ok. > > I would like to ask if you see any downside with this approach, because I > plan to do the same with another machine mainly because here NPN sensors > are way cheaper than PNP ones. > > Thanks as always for your help :) _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
