Hi I'm having a problem with my e-stop circuit.

(Gary Wilson) #1

Hi I’m having a problem with my e-stop circuit. I have connected an e-stop to pin 10 of my breakout board but nothing happens when i press it mach3 is not recognising it as working I’ve checked the ports and pins setup and everything looks ok I’ve even tried it on another pin but with no luck. Ive checked motor outputs and all seem fine but its the inputs I’m having trouble with. Also in bios I have a number of options to set the Parallel port to and was wondering if I have it set correct it is set on ECP at the moment. any help appreciated

(Grant Macaulay) #2

Does it need a pull up/ pull down resistor?
and/or configured in software.

(Gary Wilson) #3

as to the pull up/ pull down resistor no I dont think so as for configuring in software do you mean for the BOB if so then no no software for that

(Barnaby Relph) #4

What breakout board are you using? I think @Grant_Macaulay 's suggestion about pull-up/pull-down is worth double-checking. Should be switch be NO or NC?

(Gary Wilson) #5

this is the BOB I have and all the info I can find on it

(Barnaby Relph) #6

E-stop is listed as being on P12 on the eBay listing, but the diagram says that’s on left of the bank of contacts, where the diagram says you should be plugging in some form of encoder?? I don’t suppose there’s anything helpful on the silkscreen of the board?

(Gary Wilson) #7

no nothing also found this one http://www.aliexpress.com/store/product/Engraving-machine-interface-board-MACH3-interface-board-DIY-CNC-6-axis-breakout-board-PWM-spindle/324800_1096348740.html where e-stop is on p10 think i may have to ditch this board and get a better one

(Barnaby Relph) #8

yeah, that is confusing! You could attempt grounding P10 then P12 briefly and see if anything happens. It’s annoying that the hardware is probably ok, but is let down by terrible documentation

(Gary Wilson) #9

found another listing here http://www.aliexpress.com/item/Interface-Board-MACH3-Interface-Board-DIY-CNC-6-axis-Breakout-Board-PWM-spindle/1094607293.html maybe my parallel port is not set up correctly ???

(Paul Frederick) #10

Like others suggested use a pull up resistor. Pull down is kind of sloppy design really. Then connect your switch to ground. When you hit your switch it pulls the input low, and gives you a low input state. Now you have negative logic, so invert the meaning with your software. Low is enabled. This all describes a normally open switch configuration. With a normally closed you could still connect the switch to ground and use positive logic. Still use a pull up resistor to guarantee your open state level though. A common pull up resistor value is in the range of 4,700-10,000+ Ohms. Anything around there should work just fine. The resistor just has to keep the input positive until you ground it. That resistor is of course connected to your positive voltage, and the input too.

Anyhow here is the negative logic schematic http://i.imgur.com/fhxAS2Q.png

The input is high, until the switch is switched, then the input is low, until the switch is released. If you wanted to implement the positive logic you would connect the input to terminal 1 of the switch. But good electronic designers would opt for the negative logic implementation. It draws less current, and is generally more immune to noise. It is just the smart way to do it.

I don’t know how else to say it really.

(Morten Førster) #11

If you are in a high noise area (Unshielded stepper leads etc.) you might need to go lower than the 4700 ohms.

(Gary Wilson) #12

no steppers connected yet @Morten_Forster but I swapped out BOB for a different one and e-stop working good

(Morten Førster) #13

Ah, ok I’m glad it worked out :slight_smile:

(Paul Frederick) #14

I made my own BOB. It works good. It has built in pull up resistors too. http://www.instructables.com/id/Parallel-Port-Break-Out-Board-BOB/

(Eugenio Villaverde) #15

hey Gary this chinese board have a lot of problems… but if you live in usa you are a lucky man in a store http://www.cnc4pc.com you have awesome boards like c10s for pararell port i hope helped :wink:

(Paul Frederick) #16

If you want a really nice I/O board try out http://www.mesanet.com/fpgacardinfo.html Supported by LinuxCNC right out of the box!

(Eugenio Villaverde) #17

@Paul_Frederick wow its awesome lot of beauty boards :wink: thanks

(Paul Frederick) #18

Yeah Mesa is pro kit. What big boys use when they do CNC center conversions. They can handle servos. I think they can do 50MHz pulse streams? which is insane considering 100KHz is a lot on the parallel port.

(Eugenio Villaverde) #19

@Paul_Frederick i used a smoothsttepper 4mhz but the last one i try its a Csmio/p ethernet 4mhz too the 2 boards its a mach3 boards but 50 mhz its amazing, thanks

(Paul Frederick) #20

Stepper motors do not need very high speed pulse streams. Mine can’t go past 35KHz. That is about 2,500 RPM in quarter step mode too.