Ive just set up my cnc electronics for now with only wiring for x axis.
Im using the ZP5a int BOB from zapp automation.
When powered the PSU is fine, driver green LEDs are on, the motor sounds energized (based on noise coming from it) and when I run something on MACH 3 the x axis lights on the BOB flash.
However there is no movement of the motor. I cant seem to work out why this is?
Any help would be appreciated. The picture of my wiring is attached.
Are you sure Gary? On another thread there was considerable debate about the lack of source current output from the buffers on the ZP5a and the conclusion was it was better to use the BOB to sink current through the optoisolators, therefore PUL+ & DIR+ to 5v and the - to their respective outputs on the BOB and set Mach3 to 'active low'. Which is the way the OP has it wired apparently, assuming the red wire is to +5v. What's hard to see from these pics is the drive to motor wiring; to check the pairing of the 8 wires down to 4.
@skydeal do you have Mach3 set for active low and pulse length to 5? And can you list the motor wiring.
Last edited by Gary; 22-07-2014 at 08:04 AM.
Ok, but that way you're only driving the optoisolator at half the current it would prefer. Doesn't the ZP5a have a +5v out as well the N on each channel?
This is the link to the datasheet / manual.
It is a very simple breakout board and the outputs are N, S, D and E.
the board buffers the signal from the parallel port so as long as you have a good 5V to power the board you will get good +5V signal from the S,D and E connections.
The only issue we have had with this board is when the USB is used to power the board, and never had any issue with it not having enough current to power the opto on the driver.
Yes I read the manual. I'm not saying you're wrong, the board will work as you say, but the output buffers can only source 6mA at 3.8v typical output on a 5v supply. With a typical optoisolator circuit as in the MH drives (given a 390ohm input resistor and a 2v forward voltage) you'll actually get around 4.5mA , less than half what the optoisolator needs to meet the recommended drive levels in the MH driver spec, plus the active rising edge is slow due to the input capacitance which could become problematic at higher step rates. By sinking current you only lose 0.4v of the 5v in the buffer so you get closer to 7mA drive and better shape to the active falling edge so better at higher step rates and more resistant to noise on supply rails.
I guess the OP did wire it wrong as he took the + common to N and not to 5v output? If so I stand corrected on that point.
Problem solved! followed garys instructions on using connecting PUL+ and DIR+ to signal and direction and dir-/pul- both to ground. my previous wiring was based on several sources online aswell as Driver Manual, but i guess they werent specific to this BOB.
wiring was correct. done it according to this motor. http://www.zappautomation.co.uk/elec...per-motor.html.
yes my settings werent active low enabled for x,y,z. i switched them on but no movement.
but problem has been solved. followed garys advice
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