Let the fun begin !!! ???

**PAULRO** · 03-04-2015

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** · 03-04-2015

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** · 03-04-2015

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** · 06-04-2015

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** · 07-04-2015

Originally Posted by 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.?

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)

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**PAULRO** · 07-04-2015

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?

**PAULRO** · 07-04-2015

my psu breaker keeps tripping when i power up . it's a 6 amp, C rated. i think it's either the relay or the push switch i'm using .when i bypass both of them and use the switch on the door to power up everything's fine . i'll have another go at it tomorrow. perhaps a safety relay might be getting a call from the bench sooner than planned. on reflection after some reading i'm sure i will be using an input on my BOB for an E/stop. Mach 3 tutorials reveal alot!!!!

**Clive S** · 07-04-2015

Depending how big your transformer is you might have to rate the mcb a little higher see this: http://www.neweysonline.co.uk/MCBs/Static.raction ..Clive

**JAZZCNC** · 07-04-2015

I need a re-cap on what your using for the main PSU.! . . . Safety relay won't do anything for inrush current if your using toroidal PSU.
If PSU is toroidal then try a D rated MCB.!! . . . . But first you need check everything else is wired correct because the relay and switch shouldn't make any difference so if removing made a difference then suggests you got something wrong.?

Also Not sure what your meaning by using an Input for E-stop.?. . . If your meaning to ONLY use an input for the e-stop then it's a Bad idea.!! All you will be doing is relying on the Software to stop the machine which isn't safe at all.
The correct way is to remove power using relays and then inform Control software the E-stop as happened via an input. Only thing the Input is used for is telling software to stop the G-code and don't allow Control to reset until input state changes.