The strangest thing happened yesterday

[maginter]

Hi all -

I have a question for the collective. Yesterday I was running a job and had it broken into four consecutive files. I ran files one and two without issue, but when I got to file three, my bot went stupid. It was supposed to be cutting hole in a 4 x 8 sheet. Instead it cut straight lines all on the same Y axis but didn't change the X axis. I rebooted and everything came back fine other than I ruined part of the job.

Any ideas of what might have happened?

[dana_swift]

Mark can you post the SBP files so we can have a look at them?

Also did you preview the cut with the new beta SB3 software? If it showed the cuts doing what you want, you need to talk to Tech support.

D

[harryball]

So... after reboot your ran the same file without alteration and it cut properly?

Sounds like something is not right. If it were me I'd shutdown and power down. I would call Shopbot and ask what connections to check and go over everything. My concern would be a problem with the drivers and the x motors becoming disconnected which I understand can fry things.

Hopefully this is either a simple loose connection or bug somewhere... but when motors stop responding/moving I get concerned.

/RB

[maginter]

The file is bigger than allowed for upload. It is actually a section of the Vacuum box cut out. I can send it to individuals if you are interested.

It ran fine on the SB3 preview. I have an older PRT that I bought used and has a 4G Botrods upgrade. One thing that I have noticed is this controller is very noisy electrically. I can not use anything longer than a 10 foot serial cable between the controller and the computer. Also, if I turn the controller on when I have a week FM radio station on, I get a lot of 60 Hz noise. This machine has been a work in progress. The wiring was a train wreck when I got it. I have since added E-chain and laid the wiring out in a more uniform manner. I was getting data errors wheh running the file with a 20 foot serial cable. I changed the cable and repeated the run, re-booting in between. That is when this issue occured. Everything is checking out correct and all the signals and voltages are right. I am really starting to think that I am getting line noise the is corrupting the signal to the controller.

Any ideas???

[yobot]

Hi, Mark.

Just a quick sanity check.

Make sure that you don't have the neutral line that feeds the box, connected to ground inside the box. It should only be grounded at the service entrance.

Also make sure that all your grounds return to the box, not somewhere else. In other words, don't ground the bot frame to a plug on the other side of the room. Make sure that all the grounds for the bot originate from a single point (the box).

David

[rcnewcomb]

Mark,

Do you have a router or a spindle?

My thoughts are gounding issues (AMHIK) or RF noise from the spindle.

Also, on your AC power check the voltage between neutral and ground. It should be zero.

[dana_swift]

Mark- I didn't notice your point that rebooting made the problem go away. The SBP file is probably fine or it would never cut correctly.

David's suggestion of checking grounds is worth looking into, but I will wager your problem is somewhere else.

Look around to see if you can find anything obvious, loose connection inside the control box, etc. Then give tech support a call.

When you get it resolved I will be interested in the solution-

D

[maginter]

Grounds are all OK. No ground loops, or loose wires. You know the more I think about this the more I am wodering if it isn't the power supply that is in the controller box. In mine there are two incoming plugs. One goes to a "power supply" like what is used in a regular computer. The other goes to feed the control board. If the computer power supply was going bad, the noise would be a tell tale sign...... Comments?

BTW I am running routers.

[dana_swift]

Mark, I think you are on a slightly more likely path, and its easy to check out.

Do you have a storage oscilloscope? Or can you borrow one? Clip that baby to two of the power supply outputs, use both AC and DC coupled mode, and use the triggering level to find the noise level.

Check with shopbot to find out what the acceptable DC levels for the supply are. The AC noise level can be slightly "high" and everything should still be ok because of the power supply decoupling capacitors located on any digital circuit. Also look up the powersupply specs on the net.

Run your system, and see if your hunch is correct.

As I was told once when diagnosing cars: Many electrical problems turn out to be fuel! Moral: keep an open mind about what it could be and keep looking till you find it. The scope should help a lot.

When I was teaching electronics troubleshooting, the first big lesson is to make sure the power is correct. If its not, nothing will be correct.

Good luck-

D

[maginter]

Hi Dana -

You must have read my mind. I was thinking about that at work while I was collecting data for a algorithm. I was stairing at the data tool and thought, "I should do this to the Bot!" I will request the the information from Shopbot and let you know how it turns out. It won't be this weekend, but probably next.

Thanks for your input.

Mark