estop diagram

[markus_detroy]

anyone know of e stop diagram, that use a contactor to remove main feeds
but keeps pc power

[Karl_T]

I don't have anything to sketch into a PC handy.
The circuit is easy to describe. You need a NO pushbutton, labled reset. Attach it to power and then to the coil on a double pole relay,labled MCR for master control relay. Now put Estop circuit power to one of the poles on MCR. From the NO side of this pole, wire all your Estop buttons in series and then terminate at the MCR coil.

How it works: push reset button and MCR coil closes. When button is released, the coil is latched in because power is now going through the NO contact and through all the Estop buttons back to the coil. Push an Estop button and the circuit is broken, openning the MCR coil.

Now, take the other pole on MCR and put it in front of any coils or relays you want to break when the Estop is pressed.

Karl

[solodex2151]

The circuit in the Picture is what is used in industry. I was really lazy and did not draw it in Ladder Logic form, but you get the idea. Your start pushbutton is momentary. Your emergency stop should be a NC swtich that is closed when the button is pulled out (very important because you can bump it with a body part to shut off the machine versus having to pull it out.

When the emergency stop is closed and you press the start push button, the K1 coil is activated and its contacts close. When you release the start pushbutton, the coil is still actuated by itself through one of its contact pairs. The second contact pair is used to supply mains power to your equipment. If you press the emergency stop, the switch stops actuating the coil the mains power is cut off to the equipment. In order to start the machine again, you must first pull the emergency stop out so it closes and then push the start button again.

[markus_detroy]

what controls yours s2, im also assuming your using twist locking e-stop switches? not sure if the start button would be need in that case? but
depressing and (twist) releasing the locked estop state?

[solodex2151]

It is a standard estop button that pulls out and pushes in. The closed state should be when the button is pulled out. Then, all you have to do is push it in to stop the machine. This is real handy especially if a body part like your hand gets stuck in the machine. Then all you really have to do it whack the estop with whatever you can (knee, foot, torso, etc) to shut it off. It will then stay depressed until the operator physical pulls it out again.

This button is what I am talking about.

You do need the start button. The E-Stop should NEVER be the button that applies power to the system. It's sole function in life is to disconnect power to the system as quickly as possible. This combination is what is known as a manual reset.

I would also be tempted to kill computer power with this. The E-Stop should only be pressed in an emergency. An emergency would be when a body part is caught in the machine, the material breaks free of its hold downs and is spinning wildly threatening to hurt someone, etc. I also realized that it should really just kill power and if the relay contacts fuse closed, we're in trouble. So, take a look at the circuit below. The E-Stop breaks mains power completely. You have you start circuit for the manual reset, along with a stop button. The stop button will kill power to the motors and the router so you can do things like bit changes, adding parts, etc. in a safer manner. However, it doesn't kill the computer power, just power to anything with potential energy.

Does this help to answer you questions?

[solodex2151]

Markus,

I thought I would included the industry code for E-Stops. This is NFPA 79, and if you read 9.5 thru 9.63 it will explain the 3 kinds of stops.

Category 0: immediate removal of power to all machine actuators...ie unctrolled stop.
Category 1: a controlled stop with power to the machine actuators available to achieve the stop then power is removed.
Category 2: a controlled stop with power left available to machine actuators.
Each machine shall be equipped with a Category 0 stop.

9.6.3 Emergency Stop
--It shall override all other functions and operations in all modes

--Power to the machine actuators that can cause a hazardous condition(s) shall be removed as quickly as possible without creating other hazards (e.g. by the provision of mechanical means requiring no external power.

--Reset shall not initiate a restart

The estop shall function as either Category 0 or Category 1. The choice of category of estop shall be determined in accordance with the requirements of the application.

Where a Category 0 stop is used it shall have only hardwired electromechanical components. Its operation shall not depend on electronic logic or the transmission of commands over a network.

Where a Category 1 stop is used for the estop final removal of power to the machine actuators shall be ensured and shall be by means of electromechanical components.

[Al_The_Man]

Originally Posted by solodex2151 Markus, I thought I would included the industry code for E-Stops. This is NFPA 79, and if you read 9.5 thru 9.63 it will explain the 3 kinds of stops.

Most of these E-stop conditions are now done with a special relay called a Safety Relay for controlled power-down/up, almost all European equipment has them and N.Am. is now coming on board.
In the systems I install, I prefer to leave the PC or controller powered, I E-stop all output functions = power to any solenoids,spindle contactors etc
I also use auxiliary contacts on a the main E-stop relay to all the drive enable inputs. If you switch off the drive power, the DC takes a while to decay, so this method stops the drives immediately, also a contact can be used to indicate to the controller that an E-stop has occurred.
Al.