[pigifly]

Hi.
I've just finished building the simple BOB.
I will leave my experience (and all the help I will receive ) on this thread for everyone need to have help on this couple of components.

I think the job should be divided in ( at least ) a couple of step:
The very first one is to test that no ( unwanted ) current flows to the PC port.

The other one is to test that the board works correctly with the software.

Any other hints ?
How should I start with those steps ?


Pigi

[pminmo]

Pigi,
First put power on the board without it hooked up to the pc or driver boards. LED1 should illuminte. Hopefully you saw the errata in the document and installed a jumper inplace of LED2 ? Assuming LED1 illuminates, LED7, LED9, LED10, and LED11 should not. If those verify, placing a jumper accross Xhome should illuminate LED9, placing a jumper accross Yhome should illuminate LED10, placing a jumper accross Zhome should illuminate LED11.
If all is well at that point jumper pad1 or JP4 pin2 to 5VDC pad, when you do that LEd7 should illuminate.

Phil

[pigifly]

Everithing ok on this step.
Removed ( should read better the docs ) the led2 and tried every think you said.
Every led lights up as from docs.
There are few pins on DB25 that have little tension on it ( no more than 1,20 V ) but that should be ok.

Now what ? ( while waiting on L297/8 delivery )


Pigi

[pminmo]

Pigi,
Jumper a wire from Pad 1 to J. Monitoring LED7, you should be able to short alternately the RST(X8) and Estop (X7). This is the Emergency Stop Latch. The LED should hold the On or Off state as you alternately jumper between X7 and X8. If your ok there your ready to hook it up to your computer.

Consider downlaoding a parallel port monitor such as lpt.exe here:
http://neil.fraser.name/software/lpt/


Phil

[pigifly]

Also this part went well.
Ready to hook the PC, then ?
What next ?

Pigi


P.S. A little question:
the sw I've decided to use ( linuxcnc ) seems not to have the X-Y-Z enable signal on the printer port. Am I right thinking I can jumper the enable to +5V ( to keep the level high ) or it's better I use another software ?
Obviosly I will cut the lines toward the DB25 to don't let current flow to PC port.

[pminmo]

Hook up the PC and using lpt or similar monitor, you should be able to toggle the state of the home switches, estop and monitor them on the pc. With jumper JP4 IN , you should be able to set PIN 1 and control LED7.
The enable, no biggy. If you look at the BOB, R10, R8, and R9 are symbolized there for that exact purpose. Where those three components install, there is a small jumper land effectively shorting those components out. (I just noticed, that needs to documented, as I never intended those to be installed, was just an easy way in eagle to provide the physical hooks). One side goes to the db25, the other to each respective pin for enable for each axis. Slit that jumper for each of r8, r9, and r10 and you have disconnected the enable line form the bd25. You can use the pad that connects the enable line to either wire it high or low depending on which state you want or you can wire them to either pad j or l so that estop controls enable. I'm at a disadvantage here I know nothing of linuxcnc. I would suggest setuing up the software.

Phil

p.s. If you or anybody out there has a word processor compatable with Microsoft Word, I'd upload the document so the info here could be added.

[pminmo]

pigifly,
how's it going?

Phil

[pigifly]

Phil, I'm sorry but I haven't received the L297/298 IC yet.

They should be here tomorrow. For the moment I've finished the board anr installed all the other components.
We should wiat until tomorrow evening to accomplish the tests.

If you already have some tests for me I will execute it tomorrow, after installed the chip.

Pigi

[pminmo]

did you hook the BOB to the computer?
Phil

[pigifly]

Yes. I did hook the BOB to PC and everything seems ok.

The L297/8 have been installed to board, so I'm ready to test.
What to the JP3 is for ?

Pigi

[pminmo]

JP3 is for full step or half step. Jumper in is full step. I'd start testing the driver board without anything but power applied, and a jumper from JP1-1 to gnd (this diables the L298 driver outputs). When you turn power on LED1 should illuminate. Measure for 5vdc from JP4 pin 1 to pad IGND. S/b 5 +/-.2
Adjust trim pot R16 for the current limit reference voltage. With .5 ohm sense resistors for R1 and R2, the current limit voltage would be figured as Vref/.05= Imax.
So for a 2A motor Vref = 1V, for a 1A motor .5V....
What if any do you have in test equipment? Voltmeter?

Phil

[pigifly]

My setup include digital and analogic voltmeter, and I can use also an oscilloscope. I don't know very well how to use it, but I can have one ( dual trace ) if needed.

Let me see if I have understood well:
JP1(1) to gnd.
JP4 open.
test 5v from JP4 (1) to pad IGND ( it should be the same to test to one of the GND pin of JP1 isn't it ? )

How can I test the vref ?
I should test between ping 15 of L297 and gnd ?

Pigi

[pigifly]

I've noticed now that there is a pin for VREF.
Pigi

[pigifly]

Everithing from this tests went allright.
The Vref now is 1.00 V, the voltage between JP4(1) and GND is 4.98 V.
What's next ?


Pigi

P.S. Thank you for all the effort you are doing in helping me.

[pminmo]

Great Pigi,

Lets check on IC1.
Set your voltmeter to measure 5vdc. All readings with respect to Ignd or any of the even pins on JP1.
Pin 20 of the L297 should measure greater than 4volts. With the jumper still on JP1(1) you should measure less than 1volt on pin 10 of the L297. Removing the jumper on JP1(1) the reading should go to over 3.5 volts.
(revised, my mistake)
With a jumper to gnd on JP1(3) you should read less than 1v on pin 4 of the 40106, when you remove the jumper on JP1(3) pin 4 should go to greater than 3.5volts.
With the jumper on JP1(5) you should measure less than 1volt on pin 18 of the L297. Removing the jumper on JP1(1) the reading should go to over 3.5 volts at pin 18.


Did you socket the L297? What components physically were an issue?
I'm out of time tonight.

Phil

[pigifly]

Lets check on IC1.
Pin 20 of the L297 should measure greater than 4volts.

On pin 20: 4.97 V

With the jumper still on JP1(1) you should measure less than 1volt on pin 10 of the L297. Removing the jumper on JP1(1) the reading should go to over 3.5 volts.

On Pin 10: 0V if JP1(1) grounded 4.97V if JP1(1) not grounded

With a jumper to gnd on JP1(3) you should read less
than 1v on pin 10 of the L297, when you remove the jumper on JP1(3) pin 10 should go to greater than 3.5volts.

This is not Ok. Nothing change on pin 10 whenever I ground or not the JP1(3),either with JP1(1) grounded than with JP1(1) open.

Did you socket the L297? What components physically were an issue?

Yes, I socket the L297.
No one component was really an issue, but on the "end user" store, here in italy, you can't spend less than 25$ for the couple L297/, so for three would be more than 70$. I've found it in an industry store for less than 10$ for couple (a 40$ save....) but I had to wait for expedition.

Do you think it would be a bg issue the problem we have on JP1(3) ?

Pigi

[pminmo]

Pigi,
I goofed, I edited my previous post to correct the mistake. Install a jumper in JP2 jumpering pins 1 to 2. There are other checks we could make, and I can detail those out if you want, but from my long distance view, everything you have done on both boards checksout so far, seems like your done a great job building so If you are a little bit of a gambler I'd say hookup a pushbutton switch to JP1(5) with the other side of the switch to Ignd and hook up the stepper. Power it up, carefully monitoring the L298 that it doesn't get hot quickly, and toggle the pushbutton and see if the motor steps.

Phil

[pigifly]

With a jumper to gnd on JP1(3) you should read less than 1v on pin 4 of the 40106, when you remove the jumper on JP1(3) pin 4 should go to greater than 3.5volts.

No way to achieve this.
I've tried either with a jumper on JP1(5) to GND than without, with a jumper on JP2 and without, but I alway read 4.98V

With the jumper on JP1(5) you should measure less than 1volt on pin 18 of the L297. Removing the jumper on JP1(1) the reading should go to over 3.5 volts at pin 18.

This is OK.

you are a little bit of a gambler I'd say hookup a pushbutton switch to JP1(5) with the other side of the switch to Ignd and hook up the stepper. Power it up, carefully monitoring the L298 that it doesn't get hot quickly, and toggle the pushbutton and see if the motor steps.

Almost OK.
The motor moves, followin the pulses on JP1(3), but the L298 goes hot almost soon (not untouchable but can hurt if you keep the finger there), and ( and this is what frighten me) is that the motor is heavly noisy ( you know, as if it is moving but it don't ) when is stopped, while seems right when moving.

Is this behavior correct ?

Pigi

[Ferenczyg]

L298 are 2A5 rated, but for any over 1A5 must be heatsinked and any over 2A must need heatsinking and forced air ventilation.

/Fer

[pminmo]

Pigi,
As regards to pin 4, isolate it this way:
With a gnd on JP1(3):
a) pin 1 of the 40106 s/b less than .2volts
b) pin 2 s/b greater than 3.5V,
c) pin 3 s/b the same reading as pin 2
d) and pin 4 s/b < 1v.
With JP1(3) open:
e) pin 1 of the 40106 s/b greater than 4.5V
f) pin 2 s/b<1V
g) pin 3 should read the same as pin 2
h) pin 3 s/b greater than 3.5V.
Where does the disagreement start in the above sequence?
Fer is correct on the heat sink, since you set vref for 1V I would assume you have a 2A motor, it will have to be heatsinked. The failed sequence above will not allow a direction change, but if all else is correct the motor will step.

Phil