Mesa 7i76E estop

this is up to You
if in private use no need to stop the PC or Cointrolling System
if in public TAKE down all the power

if it is Critical in things of reinforce system on Switches it might be better to only take down the Power of the Motors

if Cabinet is not in Hands of User

You can remove field power with Estop with some limitations:

1. You must exit the Estop state before LinuxCNC starts
(or you must stop/start the sserial interface once Estop is removed)

2. You _must not_ switch the DC field power to the 7I76E, but rather the AC source
of the field power supply.

Phill

If your machine is for sale to the public then the estop must be implemented IAW all classification society, state and national codes. The implementation of which is far beyond a simple forum post.

A machine for personal use only requires protection to the level the owner/operator is comfortable with. If your machine is driven by steppers then I would let LinuxCNC handle all the estop problems. The stepper driver requires a constant stream of pulses (commands) to keep moving and on a hardware or SW crash usually will stop. If you have a servo powered machine or want an extra level of protection then remove the ac from the driver power supply. Even with all of my LinuxCNC hacking and fooling with controls and 100's of hours of production cutting I have NEVER had an uncontrolled run away and the machine has always stopped when commanded. Personally I would not disturb the control system power in any way in an estop situation. My commercial mill doesn't shut down the control system on an estop, it does disconnect the PM servo motors from their amps and shorts the windings with a large resistor to stop them quickly. The controller is also placed into an estop state but is still very much alive.

John

As my machine grew, I added more e-stops. The original one on the control panel was hardwired to the 240v AC feed to the 48 volt stepper controller motor. It wasn't practical to extend this to other estop buttons so I added a relay that switches 5 volt to the stepper disable signals on the stepper controllers. This necessitated building an estop chain in the hal file rather than with physical wiring. I would't drop field power. From memory, the main requirement is to disable anything that can move the machine

Also in public use there is the possibility that you stop as fast as it's in safe mechanical limits under power and cut thereafter the "power" by a safe relais. One simple way is to cut most power by the estop direct and use a timedelayed relais to keep the power where you need it to brake the mechanics.

Hi Guys,
Apologize for warming up old topic but I have similar question regarding Estop and Mesa 7i76e.

I planing to implement two E-stops into my machine. And I am not sure if this is right approach.

Currently I have physical on/off switch and I planing to add first E-stop on line cable for this switch, which breaks L on AC main line (this will cut ac on 48 PS for steppers, 24V PS for messa card 5V PS and other relays for external AC (spindle cooling system etc).
Second one connected to mesa card and mapped in hal. Here I have question.
On mesa 7i76e I have only 4 analog inputs on Pin 0,1,2,3 and I already use all of them in NC mode. On 0,1 I have Home and Min X,Y respectively, 2 pin max and home Z and on 3 I have tool length sensor. Is there any place where I can map estop ? Or I should rewire existing stuff to have home min XY on one pit which free estop?
Other thing which come to my mind is to wire this estop on the 24V to all limit switches but I do not thing this is right thing to do ? Any opinion how this should be done ? Thank you in advance.

Best regards
Michal

the 7i76e has 32 inputs. in the correct mode inputs 0,1,2,3 can read an analog voltage but you seem to be using them as a digital input. Thats fine, I do that to. so just use another spare input for your estop.

Also don't drop power to the 7i76e as the connection to linuxcnc may not able to be recovered when you exit estop.