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ATC Persistent Error

Florida Owl

Feb 10, 2022
Good afternoon everyone, and thank you ahead of time =)

I have a Mazak PFH - 5800 with Mazatrol 640M 80 tool unit cell, which is giving me fits. There is a persistent code, 304 (F104) ATC Arm Position Malfunction, that the operating manual describes as coming in when the ATC is stopped outside of its intended position and/or the cycle has not completed after +10 seconds from when the control anticipates. (This is in the error list on page 2-6)

There is a recovery procedure of course, which in quick steps involves Home 1, Machine menu, ATC Maint, MF1+ATC Ready, selecting locations and basically telling the ATC where it is again. I have performed this procedure a few times and the error remains after the cell attempts to start up again; it simply returns after about a minute. The thing which is weird is that I can jog it through a complete tool change cycle, CW or CCW, and it picks up its proper location at 65 and 180 degrees either way. I am confused: if the ATC drive encoder were incorrect, I should think it wouldn't give me the pink indications on the HMI when jogging through the rotations. I do not see anywhere that a door position switch could be located that might be causing it to think it were blocked (for the ATC door, not the operating door) and in the operating manual, no signal line is specified for error code 304 to be picked up by anything, which would make me think it *was* the encoder unless the ATC has like a cam sensor or something internally? Obviously something is telling it that the ATC isn't where it wants to be to remain safe, and it isn't allowing automatic operation out of an abundance of caution - I just can't imagine what that input might be from here.

Any thoughts are appreciated, and I hope your week has been and remains well all around. Cheers, Owl
I have ran this exact machine for the last 3 years just about. Ours actually has this same alarm quite often and I've never been able to figure out an exact cause. Oddly enough though, ours will continue to operate with the alarm and if you want to get rid of it just hitting clear even while in cycle makes it go away. Our alarm seems to always pop up when the magazine is prepping a tool while also changing pallets. My thought on this is that it's low on air due to the pallet change and the ATC wait pocket is slow to index due to it being controlled pneumatically. I turned the regulator for the machine air inlet up a bit some years ago and it comes up less often I think but on a day of nonstop production it's likely to come up on our machine.

Sorry if this is of no help but I thought I should chime in having the same machine with the same alarm. I will try to find time tomorrow to look in our manual and see what I can figure out.
If there's any chance this is a function of low air pressure, a cheap/quick test is to add a five or so gallon accumulator tank as close to the machine air inlet fitting as possible, so that you've got a reserve of air during high-draw operations.

Is the compressed air clean and dry in the shop? If there's air solenoids that could be sticking due to a buildup of dirt or oil in the workings that could be part of the problem.
Good morning all,

Thank you for the prompt replies from NH and IN, I had not considered that angle. Reading your suggestions I inspected the shifter solenoids and supply air, verifying we have 0.6MPa (something like 90psi) at the unit cell. I will speak with our senior people about adjusting that up if necessary.

One thing I did do this morning, was to get into the MR-J2 communication (this apparently sets absolute position things, among other items. See: Mazak Customer Training - How to Repair Absolute Position on MR J2 on Vimeo ) and in the internal alarm history, saw two things which I thought odd, being a repetition of the alarms S03 51 Servo Alarm: Overload 2 and S52 00E1 Servo Warning: Overload. The initial set state reported Completed, at a measurable position (0.205). Am I going the wrong direction with this you think?

Again I am grateful for any inputs, and I appreciate taking time out for this item. I am hoping, if I am able to determine a good ultimate reason for this error that perhaps it would also be helpful to anyone also dealing with it, as described above. Get ready for your weekend everyone =)