[HaWee]

And one more picture!

[HaWee]

And the last one....the bottom.....

[abasir]

HaWee,
Point-to-point wiring is more succeptible to pick up electrical noise, thus
1. Put some bypass capacitors (0.1uF) across the VCC and GND of the ICs to reduce power supply noise to the chip which may cause false signals.
2. Assuming the 5V regulator is by the heatsink, put a 470uF in parallel with 0.1uF across the 5V output and GND.
The above is not mandatory but may reduce headache in troubleshooting later

[davesaudio]

Workmanship looks great. Agree on 0.1uF caps etc
I have seen the difference between not-work-at-all and perform-as-expected
just from adding the caps!

[vacpress]

What other chips can have their outputs upped by transistors or fets?

i guess thats basically how the 297 works.. but with hbridges instead.. its odd, even though i know its probably not a problem, i am afraid of the l297s odd footprint....

[HaWee]

Originally posted by abasir
HaWee,
Point-to-point wiring is more succeptible to pick up electrical noise, thus
1. Put some bypass capacitors (0.1uF) across the VCC and GND of the ICs to reduce power supply noise to the chip which may cause false signals.
2. Assuming the 5V regulator is by the heatsink, put a 470uF in parallel with 0.1uF across the 5V output and GND.
The above is not mandatory but may reduce headache in troubleshooting later

Abasir,
Is the above mentioned also neccesary if using a stabilized power supply??

(thanks for the reply...all tips are welcome....)

[davesaudio]

I'll let abasir give the long answer,
but in case you are working on it now- short answer YES

[abasir]

Like dave said --- YES.
The electrical noise come from various sources, i.e., motor switching, router spikes, etc, not just from the power supply. They also come in from various ways, eg, inline, induced, etc. Add the caps and you'll have less to worry

[HaWee]

Okay,
I assume that you all have more experience as I do...so i just add the capacitors...

Only one more question abasir;
The 1st I understand....
the 2nd point you mention about "put a 470uF in parallel with 0.1uF across the 5V output and GND"
Why 2 in parallel? why not one bigger one? And doen't the 2nd mentioned capacitor do the same as the ones between VCC and ground from the IC 5804?

Is also a capacitor needed by the 74HC14...or isn't that an IC?


(btw. I already put a capacitor over regulator input and ground)

[Ferenczyg]

470uF and .1 uF capacitors are two different beasts, one will be electrolitic and the other tantalum or ceramic, with different objectives, that's the reason to add two of them in parallel and not one bigger.

And yes, put a bypass Cap for every IC, 7414 included, you are trying to protect all the logic from the noise .


Fer

[HaWee]

I found an electrolitic capacitor 470uF/40V and I found ceramic capacitors 82nF (0.082uF) is this also okay?.......I think the 0.1uF is only indication, or does it have to be exactly the same value?

I hope it's okay, so I can start with the finishing touch of my PCB.
I am preparing an old PC with an extra LPT port, so i won't destroy my pc's motherboard if something goes wrong.

As soon as this is finished i can connect steppers, pcb and pc together and test with master5 cnc, or something else if al works out.

And then ......start building the mechanical part of the router!!!

[abasir]

Go ahead... make your day
As you indicated, the values are approximated.

[Ferenczyg]

All related to capacitors are aproximated because medium tolerances are in the range of 25% except for some very specific (and expensive) types. Just assure you that the volts rating is over the volts you can expect to manage. Then, as abasir said.. go ahead and make your day

Fer

[HaWee]

Thanks you all,

I added the capacitors, and can't wait now to test this board.

As soon as I start testing I can also see if my steppers will be strong enough (can't imagine what 100oz-in does on a router).
I collected the steppers from old HP laserjet-printers (have four now, so can always expand to four axes if neccessary).
They only use 1.4A/5.2V , but if I need bigger motors I can hook up till 5A/100V (tip122), so won't have to build a new PCB.

I will keep you informed!!

[ezland00]

Have you tested it yet?

[HaWee]

No...not yet....i'm still searching for my spare LPT-port.
Don't want to testrun it on my regular PC's LPT-port so I'm building a PC that has a seperate LPT-port.

As soon as I have tested this PCB I will have you all informed!!
(i hope to do this this weekend)

[Ferenczyg]

A lpt-only pci card is 12-15 €, you can use one of these for protecting your regular PC at the testing.
Or try to find a cheap DOS-able laptop for your shop

[vacpress]

hawee- have you considered making a 555 timer based square wave generator to use to test the circuit? it could also provide valuable manual control while building the machine... and knowing about 555 circuits IS important in almost all electronics.... and you can start testing right away....

-vac



from

http://www.eleinmec.com/article.asp?3

[vacpress]

heres a little tidbit of PIC microchip ASM code that can create a squarewave:

loop incf GPIO,w ;reading + 1
andlw B'00011111' ;mask out un-needed bits
movwf count ;put in count

movlw .32 ;GP5 mask
xorwf GPIO ;toggle GP5

decfsz count ;delay
goto $-1

goto loop

[HaWee]

Hi vacpress,

Thanks for the help, but I think it's simpler for me to start testing right away with my old PC.

By the way....I found my spare PCI LPT port, so I now can start to build my PC and install DOS and
I think ME....(it's an old P150 with 48MB intern memory) I have troubles with installing 98se and I think I like master5 cnc software.

Maybe you guys suggest other better software to use??