On 09/08/2014 08:02 PM, lloyd wilson wrote:
> Our Techno router has started exhibiting an issue that has defeated
> several days of diagnostics; it's time to yell for help.
> We are running LCNC version 2.5.0 through a Pico PPMC interface chassis
> to the original servo amps. It has run in this configuration for over a
> year.
>
> For the last several days, the machine will randomly go to e-stop state.
> Although we see the behavior more frequently during heavy cuts, it can
> occur during g0 traverses or even while idling.
>
>
>
>
> As expected, this forced LCNC to wake up out of e-stop, but I could not
> then go to active state; something else evidently needs to be set.
>
> For now, I've got 2 regular questions and 1 meta-question:
>
> 1: Besides the digital IO input, what else can force LCNC into e-stop?
> 2: What else needs to be changed in the config files to force LCNC to
> ignore the e-stop input from the digital IO?
> 3: Any other ideas?
>
>
The E-stop circuitry on the DIO board has several layers of safety 
circuits.  You can not
defeat them with software, they are a permanent part of the board's 
hardware.
First, you might check the supply voltage between DIO board ST2 pins 10 
(+) and
9 (-).  This is the isolated +5 V supply for the sense inputs.  It 
normally runs about
6 V.  If overloaded, it may dip too low to keep the E-stop opto-coupler 
fully turned
on.  Since you say you have jumpered straight between pins 7-8 on ST2, that
eliminates anything else on your E-stop chain.  Also, check the +5 V supply
for the PPMC, if it is low, or developing fluctuations, it could be 
throwing the
PPMC into power-on reset, which will also put the DIO in E-stop.

You can check the state of E-stop with the ppmcdiags program, and 
possibly put a
variable resistor in series with the E-stop chain, and see where the 
margin is.
It may be the opto-coupler has gotten weak and needs to be replaced.

Normally, you want the DAC board's watchdog timer to be enabled, but you can
turn the watchdog off for testing, and see if that fixes it.  If the DAC 
registers are not
updated every 20 ms or so, the watchdog trips, and if the jumper is in 
the enable
position, it will cause the DIO board to go to E-stop.

Finally, noise on the IEEE-1284 cable can cause the CPU to sense an 
E-stop condition and
command the DIO to go to E-stop.  Or, noise on the D-25 pin 13 can also 
trip the e-stop
logic.  In some cases, making up an adaptor to pass all signals through 
except pin
13 can solve this problem.

Hopefully, one of these tricks or tests will guide you to the problem.

Jon

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