Guard Open

[SiJones]

Hi another guard open problem
When the machine is off the door is locked. On switching on the router, the guard open message shows up in the status box in the control panel. When the machine is on I can hear the solenoid working and releasing the door. However, when I try to home the machine the error message "machine not safe-homing aborted" with the detail "Close the Guard" is displayed and the machine will not home. Any ideas?
Thank you.

[Steve]

I have attached a circuit diagram and marked up the guard circuit.

If the guard is unlocked then the E-stop is released.

If you open and close the guard does the message in the control panel change or does it say the guard is always open?

How old is the machine?

It could be a faulty contact on the switch but you could measure this with a meter.

Pins 21 and 22 on the switch the red and yellow are the contacts that let the system know the guard status. With the power off and the guard open these should be open circuit if you measure on the relay board PL8 pins 7 & 8. They should then short out when you close the guard.

It could be worth taking the wires out of the connector too as sometimes the wires have been crimped on the insulation but the wire strands make an intermitant contact

[SiJones]

Hi Steve
Thank you for the information. Just to fill in the gaps our machine is from 2009 and Yes the Guard open message comes on and stays on immediately you connect from the software to the machine. Does this give you further clues?
Simon

[Steve]

The problem will be with either the switch or connections.

Remove the wires by inserting a small screwdriver in the slot behind the red or yellow wires. you will then be able to see where the wire has been gripped as there will be a small kink where it has been clamped. If the kink is on the copper then the connection is good. I would remove both wires and then refit them.

With the power off if you measure from the red to the yellow wires on ohms or continuity then you should see them connected when the guard is shut.

[SiJones]

Thank you Steve for the photo.
Good news is the machine is now working. I followed your latest instructions, both wires looked good and had connectivity. I did notice that the router had stopped close to its limits on the y and z axis, so I manually turned the lead screws to park the router in a better position. Some dust was evident behind one of the micro switches so this was cleaned up. Not sure how we fixed it but on switching back on the fault had disappeared. Would any of the above cause the problem?
Many Thanks
Simon

[Steve]

Hi,

The micro switches are not related to the door open message You must have moved the wires to sort it.

Let me know if you have further problems.