Let the fun begin !!! ???

[PAULRO]

yeah, the picture makes it all clear now. thanks Jazz. that's a great circuit i'll have to use that if you don't mind.
that has cleared up a lot of queries for me . the enable was really puzzling , as in do i wire it or do i leave it unconnected, but that picture, as you say paints a thousand words. if i connect the enable +,- as in the picture does that mean i don't need the enable +,- connected to the BOBs corresponding terminals?
1 last query to get me further down the road if you don't mind, am i right in saying that the limit input to the bob and on to MACH 3 is enough to get the motors into reverse when the override is triggered?

[JAZZCNC]

if i connect the enable +,- as in the picture does that mean i don't need the enable +,- connected to the BOBs corresponding terminals?

Probably not but Depends on the BOB.! . . . what are you using.?
It's common for the Enable on drives to not be connected but in this case we are using it to ensure no signals get to the drives so no movement can happen while at same time leaving the motors energised and Holding position.

1 last query to get me further down the road if you don't mind, am i right in saying that the limit input to the bob and on to MACH 3 is enough to get the motors into reverse when the override is triggered?

Yes but you have to Hold down the Override Button to allow Mach to Reset so you can Reverse off the switch at which point the Relay will stay ON and mach will remain Reset untill something changes. Over riding anything should be warned about and thats why I use a buzzer but it is optional.

[PAULRO]

i'm using a PLC4x-G2 breakout board .

[JAZZCNC]

Ok well think things could all change now if you wanted because I'm pretty sure that Bob can handle 24v thru it's inputs.? The manual certainly shows them using 12V.

So in this case you could remove the Relays and run 24V thru the Limit switches wired in series just the same but directly to the BOB Limit inputs. I think you'd still need an Over ride button as the Inputs are driving the Enable output so Mach's Auto limit override won't turn these back on.
Then connect the Enables on the BOB to the Enables on drives.

Or just go with my first suggestion if you prefer and want to play safe regards what the Inputs can handle.!

New pic.

Edit: Yes those inputs have 30V Max so your good to go with this Pic.

[PAULRO]

i have my drives on the back plate and i'm at the point of wiring up the signals from the B.O.B. . I am using shielded twisted pair, 24 awg , 6 core, for the pulse, direction & enable signals. do i earth the shield or leave it ? the cable run is not very long and its in the cabinet. i know i 'll earth the shield of all the out side cables once they return to the cabinet , (star connection). i'll be using shrink wrap to tidy up the loose ends when i trim the cable back.
i could use 8 core twisted pair ( shielded) and that would bring my alarms from all drives back to a terminal block where i can wire into from my power supply. i have to read up a bit more on the alarms though, the more i read the more questions i have!

[JAZZCNC]

Will be fine without shield to earth for short runs just try to keep any signal wires away from higher voltage wires like Mains.

[Clive S]

Paulro
I have used just cat5 twisted pair to each drive cable for the step/dir etc just keep them away from the motor cy cables.

Not necessary to screen them

[PAULRO]

i thought i had cat 5 cable but it turned out to be shielded 3 pair twisted so used that. the cat 5 cable wil surly turn up now that i have the drives wired. i have yet to wire the fault terminals from the em806 drives to the dedicated estop input which disables the drives once triggered but i can't find any examples on the forum so if any one can shed some light to get the subject......... i also set the micro stepping to 1600, is this o.k.?

[JAZZCNC]

i thought i had cat 5 cable but it turned out to be shielded 3 pair twisted so used that. the cat 5 cable wil surly turn up now that i have the drives wired. i have yet to wire the fault terminals from the em806 drives to the dedicated estop input which disables the drives once triggered but i can't find any examples on the forum so if any one can shed some light to get the subject......... i also set the micro stepping to 1600, is this o.k.?

1600 MS is fine.

Several ways to use the Fault signal but an easy and safe way is use a Relay with the coils wired in parallel running thru fault signals set Active low and the E-stop running thru a NC contact. This way when any of the drives fault triggers it turns on the relay which opens the NC contact triggering the e-stop.
The E-stop should then kill power to the drives which in turn drops power to the relay allowing E-stop Reset and the drive fault is cleared because power was removed and fault reset on new start up.!

Other way is not very safe as it's relying on control software to stop machine but very easy to wire. It also doesn't clear the fault so you'll need to reset the drives manually. ( For this to work set Input to Active High in Mach3)

drawn both to show.

[PAULRO]

Thanks for that Jazz, i got totally confused trying to accommodate a hardwired circuit with the e stop and an alarm input to the BOB( both versions of what you have sketched). my BOB has a dedicated input for force turning off the ENABLE, at least i think that's what it does. i'm trying to use just 1 relay and as it stands and i have that in the PSU & e/ stop circuit. I have updated the dwg to reflect what i think is your schematic. i probably don't need an input from the alarm drives to the BOB. i got caught up in thinking that an input to MACH 3 was required. i also had a look at Eddies dwg and saw that the alarms from his drives were in series so that added more ??????. as in connecting a ground wire to the positive terminal of the alarm drive and out the negative terminal and on to the next drives positive terminal etc. that really had me confused along with a dose of the flu which got my head in a spin. i don't need an e/stop signal to the BOB so on reflection , or do i?