Gecko Faulting and Mach3

[lifestill]

Please excuse me if this has been asked before or is a stupid question.

Here is the scenario.

While I'm running a routine, sometimes my Z axis gets out of sync with the encoder and causes a fault on the gecko (320's). I'm still trying to figure out why that is, but in am not sure if this can be one or is suppose to happen. It's always while picking the head up. If the routine asks the head to move up 1" and rapid to another location and back down 1.1", but the gecko has faulted only moving up .5", I have a real problem. Mach 3 does know that the gecko has faulted and in some cases I don't either until the head comes down further than anticipated.

So now for the question and I sure you all know what it is.

1. Is their any way to have Mach3 stop on gecko faults? Seems like Mach 3 should know whether the head has moved or not.

Thanks

[routerman]

Same old problem, people buy 320's even though they fault when you sneeze on them.
They trip out at 128 counts, which is easily hit with a sudden move.

What count encoder are you running ? best not to run higher than 250 counts, but then its as coarse as a full step stepper and not nearly as accuarate.

There are a number of far better drives out there that may cost slightly more, but won't send your blood pressure through the roof.
Get a drive that can run a high res encoder and produce smooth fault free motion.

[tauscnc]

I don't think Mach 3 has the closed loop system but I think you can setup the gecko so if it faults that axis (or all turn off). I believe you than need to give the system a +5V for 5 seconds to reset.

I am just going from memory...
Hopefully someone can comment more.

taus
www.cuttingedgenc.com

[lifestill]

I'm not sure what the encoders are since I didn't build the machine. I was hoping since I bought a ready to run mill, I would be able to just make chips. Unfortunately, that was not the case. I'll contact the company I bought it from to find out the encoders. What drivers were you referring too? I don't sneeze much, but am tired of getting frustrated when a piece get ruined due to a fault.

I'll look in to the delay on faults.

Thanks

[TOTALLYRC]

Please excuse me if this has been asked before or is a stupid question.

Here is the scenario.

While I'm running a routine, sometimes my Z axis gets out of sync with the encoder and causes a fault on the gecko (320's). I'm still trying to figure out why that is, but in am not sure if this can be one or is suppose to happen. It's always while picking the head up. If the routine asks the head to move up 1" and rapid to another location and back down 1.1", but the gecko has faulted only moving up .5", I have a real problem. Mach 3 does know that the gecko has faulted and in some cases I don't either until the head comes down further than anticipated.

So now for the question and I sure you all know what it is.

1. Is their any way to have Mach3 stop on gecko faults? Seems like Mach 3 should know whether the head has moved or not.

Thanks

The gecko drive has a err/reset connection. It can be wired to the estop circuit, but not directly, to let mach 3 know that there is an error problem, or possibly the pause button. Seach the zone as somebody had a wiring diagram to do just what you are looking for.

It is my experiance that the following error limit gets hit during rapids most of the time and is an indication that you are asking the motor to go faster or accelerate faster than it is capable of. You are rapiding up against gravity which is why it faults on the up move. on the down move gravity is pulling the head down and helping the motor to go fast.
The other time it is when you run into something solid that the drive can't push the machine thru. Try lowering you accel for the z axis and maybe run a little less max speed also. Gecko is going to allow setting the following error on the new G380 which is going to be out early next year (Q1) if I read the tea leaves correctly. 128 is quite a small error, but it does keep you honest as it will fault out if you are too far off the path.

Sneezing is not in the drives programing and will not affect it at all. Must have good antivirus protection


Mike

[BobWarfield]

FWIW, CNC4PC makes a "Master Control Board" that will manage the Gecko fault signal. It will trigger an E-stop if a servo faults so you don't just keep going.

RE sneezing and wishing you could ignore the sneeze without raising blood pressure, you'd have to ask yourself how far off 128 encoder counts is and how badly you want to just keep going without knowing you'd been that far off. On my IH mill, 128 encoder counts would be 0.009". I don't know about you, but if my CNC is only accurate to a 100th, that's not exactly the performance I'm looking for. In fact, that's a serious blood pressure problem right there if parts are coming off that are that inaccurate.

I'd want it to fault and I'd want to then go figure out why it faulted.

Cheers,

BW

[CJL5585]

Quote from TOTALLYRC:

It is my experiance that the following error limit gets hit during rapids most of the time and is an indication that you are asking the motor to go faster or accelerate faster than it is capable of. You are rapiding up against gravity which is why it faults on the up move. on the down move gravity is pulling the head down and helping the motor to go fast.

------------------------------------------------------

I totally agree with the above statement. I am running 3 ea. Gecko 320's and almost never have an error. The acceleration should be reduced on the Z axis, or the feedrate g-code could be lowered in the program.

[THend]

I am looking into the CNC4PC card and optical home/limit switches. I've had my G320s fault out as well, and Mach3 kept on trucking... Fortunately, the current electronics setup is that if one drive faults, they all fault...or at least I think so because I've never just run away on the two axis that didn't fault.

[Torchhead]

Running multiple servos and dealing with faults is always a fun time. One of the reasons we ended up with a processor chip in our ESP Power Controllers is to not only e-stop MACH on any drive fault, but to actually shut down the motor power THEN let that e-stop MACH and then "remember" which Gecko faulted and report it to an LED dashboard and the Screen in MACH. Besides the servo faults, we shutdown on overload, overtemp and overvoltage so we had to have a way to display WHY it shutdown.

Since the processor lives at the Gecko bus potential and reports back the errors via an isolated serial connection it can look at each individual Gecko (Up to 6) and spot the suspect without guessing. The error outputs will not drive an opto directly so you have to have some added interface to tie them back to the inputs.

Isolation of inputs is essential. We also adhere to the recommendations of the encoder vendors and have a differential cable driver/receiver to stop any encoder noise from causing a position error or drive fault.

It ends up being a little more than just a simple BOB or a couple of connections.

TOM Caudle
www.CandCNC.com
Totally Modular CNC Electronics.