**RESOLVED** Limit switches

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PaulIngram
Posts: 25
Joined: Wed Jun 02, 2010 6:25 am
Allin1DC CNC Controller: Yes
CNC Control System Serial Number: Multiple
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: No
Location: UK

**RESOLVED** Limit switches

Post by PaulIngram »

Hi

Retrofitting a BP clone mill with Mach3 and DC3IOB.

I am Just getting to wiring up limit switches on My DC3IOB. The diagrams all assume seperate limit switches for the + and - limit of each axis. My machine has single limit switches for X and Y and although there are 2 switches for Z, they are wired in series so act as a single switch.

Will it be okay to wire these in as is and defeat the unused channels or do I really need to wire in seperate switches for each end of each axis. This is doable and if it has to be done then now's the time but if the extra switches and wiring arent necessary, then that would be handy.

Thanks

Paul
cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Limit switches

Post by cncsnw »

You can get by without the additional switches.

Decide which way you want X and Y to home: usually X-, Y+ (table right, saddle forward). Wire your single switches in as those switches (e.g. wire the X switch as the X- limit, and the Y switch as the Y+ limit. Defeat the other switches at the DC3IOB (e.g. defeat X+ and Y-).

Be sure you set up your software travel limits correctly.

If you ever move onto one of the single switches in the wrong direction (e.g. jog onto the X+ switch before you have homed the machine, or set your software travel limit too long and run into after homing) then you will be unable to jog off the switch using motor power: because the switch is wired in as the X- limit, the DC3IOB will inhibit minus movement of the X axis when that switch is open. If you got onto the switch moving plus, and need to move minus to get off of it, then you will either have to power off and turn the motor by hand (difficult on a Bridgeport) or you will have to temporarily defeat the tripped limit.

Since you have two switches on Z already, you should wire them in as separate limits.
PaulIngram
Posts: 25
Joined: Wed Jun 02, 2010 6:25 am
Allin1DC CNC Controller: Yes
CNC Control System Serial Number: Multiple
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: No
Location: UK

Re: Limit switches

Post by PaulIngram »

Hi

I wired the limit switches and E-stop as shown in the documentation.

I have bench tested the kit as per the instructions, all fine.

Tying to repeat the exercise with the kit mounted in the cabinet, Mach 3 permanently shows all the limits as tripped, even if I disconnect them and try to override with the dip switches on the DC3IO.

Hopefully this is something stupid and simple, I've just spent a few hours now going through and checking everything, but cant find the problem.

Any sugestions ?

Thanks

Paul
diycncscott

Re: Limit switches

Post by diycncscott »

Paul,

Mach communicated correctly on your bench correct? estop, limit switches etc.. toggled correctly?

Make SURE that the DC3IOB and MPU11 are powered up simultaneously - if they are not, the MPU11 will not auto configure for the correct type of drive/plc and your drive and I/O won't work.

Check your fibers, you could have the fibers mixed up, Do you see "Ajax Hardware detected" in the "status" window in the lower left of the scrren when you start mach? If not it's probably that your fibers are out of order.

If you do see so "Ajax Hardware detected", try disconnecting all limits, estop and anyother external device from the DC3IOB and it's power supply. Does it work now using the defeaters to toggle the limits? The only thing I can think of is that you changed your mach configuration for limits in "ports and pins" -> "inputs" to be active high instead of active low. Make sure they are active low.
PaulIngram
Posts: 25
Joined: Wed Jun 02, 2010 6:25 am
Allin1DC CNC Controller: Yes
CNC Control System Serial Number: Multiple
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: No
Location: UK

Re: Limit switches

Post by PaulIngram »

Hi Scott

Yes, it did communicate correctly on the bench.

Both devices power up simultaneously, both on the same breaker.

Fibres, I will check. These sound like a good bet.

I dont see Ajax hardware detected but I do see "no longer receiving packets from Ajax hardware" when I power it down. I will clear the messages before powering up to see whether it actually appears.

I have already tied disconnecting the limits and estops and toggling the defeaters and no response.

After trying it on the bench a week or so ago, I logged it out and powered it down straight away, I will check the config to make sure that ports and pins are active low.

It looks like the fibres are the best bet.

I'll lket you know how I get on.

Thanks

Paul
PaulIngram
Posts: 25
Joined: Wed Jun 02, 2010 6:25 am
Allin1DC CNC Controller: Yes
CNC Control System Serial Number: Multiple
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: No
Location: UK

Re: Limit switches

Post by PaulIngram »

Scott

As you suggested, it was the fibre connections.

I was using one of the legacy ports in error.

Thanks.

Paul
diycncscott

Re: Limit switches

Post by diycncscott »

Hi Paul,

Glad to hear you're back up and running.

Regards
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