[pgarr54932]

we just got a mighty comet with a mits 320 cnc. we are getting a T bus error. All suggestions are greatly appreciated.

[camsys]

In your post you mentioned that you just acquired this machine, so have
you run any jobs on it?

Did you see the machine operating before you received it?

I ask because there are a few posiibilities that produce a BUS error....

Is there any other information in the alarm message, such as a code
that may say Y01 , Z01 etc... Are you able to page over to the diag -> alarm
screen and verify if there's any other codes..

Mits alarm page will say something like Z31 DATA ERROR 0001

If you cant page over to the alarm screen, and only see BUS ERROR, that refers
to non-existent memory being accessed... which might mean that system software/ladder has been lost.

If there's a Y code associated with the message, then that means that the MCP has lost connectivity with the drives, check cabling to resolve this.

Another possibility is that the CPU itself has malfunctioned.

[pgarr54932]

First of all thank you camsys for helping us.
We did not see the machine run but a service tech on-site powered the machine up and ran all machine functions in manual mode, as it was reported to us. We see a L bus error first, when powering up and selecting manual mode. We can reset this error and run the machine via MDI. Main functions seem ok, spindle on/off @ different speeds, axis jog, spindle fwd/rev. We can call a tool and the turret will index the proper location. Immediately upon cycle start with the M6 command we get the T buss error. The control is now locked up and there is a display of data that fills the entire column of the screen located at about the right third of the display. The cnc will remain locked up until we cycle power.

[onthebumper]

You may need to format the control. This will clear all of the machining programs, Tool Offsets, and Work Offsets but will not clear the parameters. It's not a difficult procedure but there are many steps. You should call Mistsubishi (847-478-2500) to walk you through it or search up other posts here to see how it's done.

[camsys]

I believe it's a good idea to try to reformat memory, and see if this clears
the problem.

I believe your error messages are generated from the PLC , since an M6
is something that the machine builder incorporates for their particular machines.
If you still have probs after reformatting, there may be some other possibilities.

Keep us POSTED!