Emco PC120 Turn

[Chaz]

Without reading back through the thread to see what you have or have not changed, can the stepper drivers handle the extra voltage?

I'd suspect they've just used a generic power supply, rather than have two different ones, so you will most likely get away with a smaller one if one only powers a single motor.

I dont have the motor spec and I am reluctant to start removing bits. Probably the easiest to do is simply put back a 24V 10A supply which will cover all my needs. I have a 24V 5A already which is being used for another machine - ill move this across, make sure it all works and then buy a larger din rail unit and rewire where needed.

[Chaz]

Ok, using a 5A PSU and a new BOB, we are back to where we were. However, I cannot get the relays to switch.

Click on coolant, the 5V relay on the BOB clicks, light comes on, IN1 (Input 1) on the Relay board switches. The problem is that the relay state on the relay board doesnt change. If I remove the jumper (what does it do?) the relay makes / breaks but that is manual. If I try and bridge to the other side the BOB boards dim and its clearly not happy.

Any ideas? My 5V light on the PSU is also not active however I can measure 5V (PC voltage) across the pins. Is my wiring correct?

[Chaz]

OK, its working. Looks like the relay board must have been damaged. Had bought a 2nd one as they were cheap. Now works :-)

Wow, what a mission.

[Chaz]

Ok, its working however at startup the boards 'click'. It did not cause a problem at first but now the coolant pump starts / stops as the relays change state.

Any idea what can be causing this? I tried a different 5V supply. I believe the 24V supply can offer enough current. I cant see any voltage drop as such.

Could it be Mach 3 initalising as the PC boots up? Not sure if I can create some form of 'dont power anything till everything is ready' steady state. The PC currently is fed from the same power as the CNC. Perhaps I should power the PC on its own and see if this still happens during the machine start up.

Once everything has been booted and settled, the clicking goes away.

[m_c]

Are you using a charge pump?
If not, it sounds like the parallel port doing random things as things boot up.
If you've not got a charge pump, a quick fix would be an extra switch to keep the lathe powered of until the PC has booted. It's not ideal, but it would work, provided you remember to turn things on in the correct order.

[Chaz]

Are you using a charge pump?
If not, it sounds like the parallel port doing random things as things boot up.
If you've not got a charge pump, a quick fix would be an extra switch to keep the lathe powered of until the PC has booted. It's not ideal, but it would work, provided you remember to turn things on in the correct order.

Not sure what a charge pump is. It has a normal 24V contractor that fires up the coolant pump (single phase probably around 0.3KW). I may disconnect the main motor drivers and see if it still does it. Something seems to want to initialise. It could be the PC too, its not a good machine as such but we are fairly limited with the older interfaces (unless there are trust worthy add on cards for newer machines).

[Chaz]

Are you using a charge pump?
If not, it sounds like the parallel port doing random things as things boot up.
If you've not got a charge pump, a quick fix would be an extra switch to keep the lathe powered of until the PC has booted. It's not ideal, but it would work, provided you remember to turn things on in the correct order.

Actually, id go CS Labs for the simplicity however not value for money at present. I could look at something like one of the smoothieboards or something that is better than the BOB but less expensive than CS Labs.

[m_c]

A charge pump is a device that needs a fixed frequency input, at which point it then activates, and is typically used on BOBs to ensure no outputs are activated until the charge pump is active.

The problem with a parallel port, is the pins may switch on/off during power up/initialisation. By using a charge pump, it means the parallel port driver has to be full control, and generating a fixed frequency output, before any outputs get activated. It also provides some safety in the event the computer crashes, as it should cause the charge pump to fail and deactivate outputs.

If it's just the coolant switching on, I wouldn't worry too much. The big concern is if the spindle happens to activate, or anything else that could cause physical damage.

[cropwell]

I would only add that my experience of a charge pump on a Chinese BoB with no worthwhile knowledgeable support coming from the supplier (in Devon), I ended up disabling it and have a switch for my spindle (so I can change a tool without losing another finger end) and a switch for the air blower.

That was when I first started using Mach3, I probably could figure out how to enable it properly now, but it isn't on the BoBs I use now and I have got used to being without it

Cheers,

Rob