Let the fun begin !!! ???

**Clive S** · 25-03-2015

Originally Posted by PAULRO

i 'm just getting back into the build today and i have the electronics mounted on the back plate. i have a query regarding the fuses for the 70 V DC power supply. i have the fuses on the negative side of the supply , is that o.k. ?

Its good practise to put fuses in the +ve side and the mcb for the input to the transformer appears to be 3A I would think you need more like 6A because of the inrush to the coil and rate it to a motor type ..Clive

**PAULRO** · 25-03-2015

cheers Clive , i have a 6A in there , i just for got to update the dwg.! i better change the fuses around .

**PAULRO** · 26-03-2015

O.K. state of play so far is that i have the back panel in the cabinet and i'm doing some electrical dwgs so i can at least give myself a fighting chance to get it right . i have a couple of queries before i go and start lashing in wires though. this is what i think i know from reading the posts , so i just need some nudging .

1......am i correct in saying that i need a separate input for the slave home switch?
2 .... i need a separate input for the rest of the home switches combined in series.
3... because i'm combining both limits and home into a single switch i must keep the e stop on a separate input.
4... i also need an input for feed / hold
5..... and an input for stop.
bring my total of inputs to 5 ( MAX. allowed)

i also have alarm terminals on my drive so i'm curious about how i can get these in to an input. i will post some drawings of my proposed electrics as soon as i'm finished.

**Clive S** · 26-03-2015

Ok
1: = yes
2: = yes
3: = yes
4: = yes
5: = yes
You can add an extra two BOB's to your motion controller if you like then you would have 15 inputs. ..Clive

**JAZZCNC** · 26-03-2015

If your going to have a feed hold button then you need a Cycle start button to get going again so you'll need an input for that. No point having External feed hold button without cycle Start.!

Also with homing and Slaving then you need to make sure " Home slave with Master" is UN-Ticked in General Config.

Also UN-Tick " Home sw Safety" if your sharing limit & home switches as the switch will be treat as Limit when homing and E-stop the system.

With #3 then you don't need E-stop on it's own Input if wired in series with limits just Set the E-stop Pin to same number as the input your using.! Then when switch is pressed Both Limit and E-stop Led will light in Diagnostics.

**PAULRO** · 26-03-2015

I thought that if i use 1 input for the limits and estop i won;t be able to reset because the m/c will be on a limit thereby inhibiting a reset. or have i got this all wrong? i think i will leave the feed / hold out for the time being and just go with e/stop, stop, limits /home, and A home. at least until i become more familiar and have a better understanding of the process. I also have another input dedicated for force turn off enable so i will use this to take a fault signal from the drives.

**PAULRO** · 26-03-2015

I couldn't upload a PDF so i had to save as a jpeg. who needs it? Anyway , here's my proposed wiring diagram for the BOB. I have 1 more input left. XP30 is a dedicated forced turning off ENABLE. My understanding of this is that if a fault occurs in a drive then the alarm will trigger an input to XP30 and the drive will be disabled. is this a correct assumption?

**JAZZCNC** · 27-03-2015

Originally Posted by PAULRO

I thought that if i use 1 input for the limits and estop i won;t be able to reset because the m/c will be on a limit thereby inhibiting a reset. or have i got this all wrong?

Sorry delay replying went out last night for a pint which turned into Gallon then Amnesia.!! . . Well No and yes to getting it wrong.?
Mach as feature called Auto Limit Override which lets you Reset after Limit trip so you can Back off.

But With the E-stop then if your combining Limits and E-stop in same circuit and using Relays for hardware driven system (which you really should be) then you will need some Limit over ride Switch to reset the Relays. If using this setup then you can use the same Relay to inform Mach e-stop Happened and then just set Limits to watch same Pin if you want. With a Hardware driven safety system all your really doing is informing software an E-stop happened so it halts the Code and won't Reset until fault cleared. The actual safety side is done by the Relays and Never should be done by software.

Now personally I don't combine E-stop and limits because limit trip isn't an Emergency it's more positional error. I have Limits and Homes combined and limits do 2 jobs they Inform the Control limit as tripped and they disable the Enable on the drive so Motors are still locked but won't recieve signals.
Again a Limit override button is needed if disabeling the Enables on drives. If you don't disable the drives and just Inform the control you can get away with using Mach's Auto limit override feature.

**PAULRO** · 26-03-2015

Ok
1: = yes
2: = yes
3: = yes
4: = yes
5: = yes
You can add an extra two BOB's to your motion controller if you like then you would have 15 inputs. ..Clive

maybe down the road i might contemplate an extra BOB . i have to get this set up right first and get very familiar with the whole process.

**PAULRO** · 27-03-2015

right guys, this is probably a dumb question but i ask it any way, if 1 switch can be used as a home switch and limit switch to monitor an axis ( that's 4 switches in total for X,Y,Z, including a separate switch for the slaved A axis home) why would some builders need 3 switches per axis , total of 10 including a separate switch for the slaved A axis home? if the limits are separate to the home would they not need an extra input to the already limited no. available on the LPT port? there is also a cost factor for the extra switches. i have to be missing something here.
My build so far has accommodation for an e stop hard wired to drop out the drives and as an input to the BOB for MACH 3. is there a need for a hard wired stop switch on the panel door? and if so how does it differ from an estop? I'm sure i can stop and pause the machine from MACH 3. is this adequate?
is it ok to use the main switch to drop out the power supply to the drives or should i have a switch after the power supply to control the drives and leave the power supply powered up when configuring the drives. does it matter?
i think i'm at a stage where i need to get the machine up and running with an adequate level of safety built in. i can then add the extras as i become more familiar and comfortable with the experience. any thoughts on the above would be appreciated.