[wmpy]

I have a 1989 Mori Seiki ZL-15 with a Fanuc 11TT Model A control. The belt on the lower X-axis broke while cutting which caused the turret to fall down to the bottom of its stroke limit. I replaced the belt, but now when the machine is powered up, I get an -X2 stroke limit alarm if I try to move it in the -X2 direction. This makes sense because of the turret falling and me hooking up the belt at that fallen position. So, I opened up the -X2 soft stroke limit and zero returned the machine. I put the stroke limit back to where it's supposed to be, and everything is fine. The problem is that when I restart the machine, I have to do the whole process over again. The machine at home position will give me a machine position of approximately X2 -7.5000 upon power up. As soon as I try to move in -X2 direction, I get the soft overtravel alarm again. I tried doing the P Cancel thing, but that does nothing. I want to know what I can do to get the machine to forget its old position. It's behaving like it has absolute pulse coders, but from what I understand, this machine is too old for that to be possible. So far, Fanuc has been unable to help me, so I'm hoping someone on here has an idea what might be going on. I know that I could just disconnect the belt and jog the motor to where it's supposed to be, but I'd like to know how to do this with the control. Plus, I'm quite perplexed and really curious what's going on here. Thanks.

[stevo1]

Sounds to me like you are going to have to adjust your gridshift parameters which in your control will be 1850.

Stevo

[cnc2149]

The 11 could support absolute pulse coders. What do you have in parameter 1815 for this axis?

[wmpy]

That would be a very large grid shift. I'm pretty sure it would be over the limit. I'll check the 1815 parameter tomorrow when I get to work. Thanks!

[tc429]

sounds like absolutes...our sl-25s do the same thing if they get lost... As I recall, turn off the apc/apc bits in 1815 for that axis, jog to wherever you want to call 'home', turn them back on...cant recall one has to turn on before the other, cycle power, turn on the other, cycle power again...easy standing in front of the control, but cant picture the sequence from here

[stevo1]

I am not sure what the limit is on the gridshift or how far exactly your machine is off. If it cannot take the large number and you do not have ABS encoders then I believe the only thing you can do is as you stated above. Take the belt off and move the axis back closer to home and then use the gridshift parameters for the fine tuning.

Stevo

[wmpy]

parameter for 1815 shows 00110000. What does this mean? My book only gives descriptions for bits 0 and 1, which are RES and OPT. There's no mention of APZ or APC. Maybe I have the wrong book? The book is for an 11TT model A. Maybe I have a later model?

[wmpy]

tc429, what years are your SL-25s? What controls?

[stevo1]

It looks to me that you have abs encoders. You need to reset your position. Attached is not your manual but tells you how to do it.

Stevo

[wmpy]

Success! I set the APZ bit to zero, cycled power, homed out the machine, cycled power, and the position stuck! I guess I really do have absolute pulse coders. I just don't understand why both Fanuc techs told me that there was no way I could have them on a machine of this vintage. They also told me that if I have decel switches (I do), I don't have absolute pulse coders. I guess the lesson learned here is that the Fanuc techs don't always know what they're talking about. Thanks to everyone for the help!

[stevo1]

I’m glad you got it up and running.....Good job!!!

The machine could have originally came with inc encoders and had been replaced during a rebuild or if the motors went.

Stevo

[underthetire]

Mori did have abs encoders on the 0, so they may well have had them for the 11. One way to know is if it had 2 sets of d cell battery holders.

[wmpy]

There are two sets of D battery packs- one square and one rectangular. So, it probably came with absolute encoders from the factory. I guess Mori was just ahead of their time.

[underthetire]

Not probably then, it did. Mori was really competing with okuma back then, okuma had them long before that.

[alexfanuc]

I´ve seen those machines with absolute pulsecoders. They have the dec switch because when you loose your home position you just have to zero return and it will automatically home. When you loose the home position you will have in parameter 1815 00100000, bit four will be a zero. When you home the axis the parameter becomes 1815 00110000. This is why they had the dec switch. (Too expensive! for them as they later found out)