[dark_blue]

I have Mitsubishi Meldas 500 with this error only:
Z71 DETECTOR ERROR 0001 Z
I'm trying to figure out what the problem might be, so I found this information, but it doesn't help me much.

Attachment 478952

Is this a problem with the encoder?
The zero point could be initialized without problem.

[MrMetric]

It seems pretty clear to me, honestly.... There is a backup battery on the servo amplifier, and it seems like that battery needs to be replaced. If you do *not* have a battery, then the confusion on the error makes more sense to me. In this case, you probably have bad parameters and may well need to replace the battery on the Meldas NC unit itself.

[dark_blue]

Ok, thank you, I found that there is a battery for the controller. We changed about a year ago a battery pack with 4 batteries probably for the drives, and we missed this one.
Attachment 479014
After the change we will see if it will solve the problem.

[MrMetric]

Awesome! Be aware that you need to have your machine ON (not just the power switch, but also the control) to charge the NC battery (not sure about those on the drives). Also, I have an M3 control so the batteries and such might be slightly different. That said, I know the M300 is basically an M3, and I want to say that the M500 isn't too different. Maybe you can put some photos up of the drives in question? I ask this, by the way, because the battery picture you have shown is of a different type than one would typically find in an M3 or its MR-S11 type drives.

Best practice for an M3 would be to turn the machine on for a while before changing the control battery. The reason for this is that there is a series of super capacitors that will temporarily retain the memory while the battery is being changed. How long? I have no idea.... I would try to be moderately expeditious though. Reloading a machine is a bit of a paid (of course, you *should* have made a backup of all areas, I hope!). Again, much of this "knowledge" comes from the M3/M300 control, so bear in mind that my information may have limited use. :-)

Good Luck!

[dark_blue]

Hello, I replaced the battery, but the problem remains. Still showing the same error.
I also checked the recently replaced other batteries, they are four in a package, all are well.
So the batteries are fine, how to check the detector?

[MrMetric]

If you are absolutely confident that the battery is in good condition, I would say that the likely problem is with the drive itself. My first area of concentration would probably be on the daughter board upon which the battery is mounted. There is going to be a detection circuit there which is probably faulty. Finding the fault is going to be something that would require knowledge of circuitry though. It is not going to be for the feint at heart.... There is a step you can perform to help bolster your confidence that a board failure is, in fact, the cause, but this is not without its own risks and complications. You would swap the daughter boards between a drive that doesn't have the error and the one that does. The risk here is that anytime you mess with boards, you run the risk of damaging them or the drive. It *probably* isn't a high risk, but it absolutely exists. In addition, you have to be aware you will lose the position of the drives, of course. As such, you will need to perform whatever is required to get back to the known state.

Needless to say, you go down this path without any warranty, etc. You accept 100% of the risk. I'm just spewing forth ideas to consider, not providing tangible advice.

[Cenar]

Hello, I replaced the battery, but the problem remains. Still showing the same error.
I also checked the recently replaced other batteries, they are four in a package, all are well.
So the batteries are fine, how to check the detector?

Hello, I hope You did make your machine working again. Unfortunately I'm facing similar problem to Yours, one of the axis on machine with Mitsubishi control continue to give me unable-to-cancel Z71 alarm. I think we've tried everything to figure out the reason (switching drives, motors, power and encoder cables, SH21 (battery->drive system->PLC) cables, batteries itself also with cases) but the control still saying that this particular axis have battery problem. Last thing that is left unchecked is HR337 PLC (i think) card - all drives finally connects to it with SH21 cables to terminals SV1 and SV2. I don't have spare card to try replacing it, also I don't know if it is just plug&place. Unfortunatelly Internet is very short with this Mitsubishi control, the one and only forum thread corresponding to my problem is this one. Would You share your way to solve this problem? It may be helpful. Thank You in advance and have a nice day!

Greetings from Poland,
Thomas

[MrMetric]

but the control still saying that this particular axis have battery problem.

Can you clarify this a bit more... Are you saying that the problem remains with the same AXIS (X, Y, Z) after swapping the MR-S11 servo amplifiers (for instance, moving X to Y and Y to X), or are you saying that the problem follows the servo amplifier (so, the problem was on the X axis, but after moving that amplifier to the Y axis, now the issue is on the Y axis")?

(sorry... the MR-S11 is an amplifier for an M3, which is a generation before the M500, but the comment is otherwise the same.... Please also confirm that you have an M500)

[Cenar]

Thank You for quick response. The first case that You described is my case - control is giving error for Z4 axis, there is no difference after replacing all that stuff I was talking about. So it seems not to be a drive unit, nor the battery, motor or cables.
To the second question I've checked it somehow and it looks like this control is Meldas M600 (when I go to Melscreen tab, during loading there is sign "MELDAS M635" or so), and all drive system units names start with MDS-C1. I don't know this Mitsubishi nomenclature, I'm closer to Siemens and Fanuc, this machine is the only one on Mitsubishi that I've known. I'm suspecting that there is a problem with PLC itself, couple months ago we've faced a problem with turret encoder - it came out that one of resistors on mentioned board - HR337 - was blown. I've managed it by resoldering new one and machine was ok till today. But I'm still wondering if there is some trivial thing I haven't checked yet, that's why I wrote here.

[MrMetric]

I think your diagnosis steps are probably valid and well thought out. I'm puzzled by where the problem may be.... I don't really think the PLC would be the issue because the PLC is more about "customization" of a control to a specific machine's mechanical configuration. Your problem feels more like it is deeper inside the system, at a level where the firmware is talking directly to the hardware. The part that really confuses me is that (based on the error message), I would have suspected that you might have something bad in the circuit that measures the battery voltage for the axis having the problem. However, I would expect that logic to be *on* the servo amplifier itself as that is where the battery is connected. If that were the case, then the fault should have followed the new axis to which you moved the servo amplifier....

I assume that when you swapped the drives, you kept the battery with the drive (so you moved that battery to the new axis too). Right?

Honestly, I think I am out of ideas here. I am only going on what I know about the older controls, and even then, I am working on assumptions. My machine does not have absolute positioning, so I do not have batteries on my servo amplifiers. I'm sorry, but I don't think I can really help anymore. . I would suggest that you reach out to Mitsubishi. This seems like it is something that their customer support should be able to provide some guidance. Your control is new enough that I would think they have people familiar with faults such as this.

Best of luck!

[MrMetric]

Is it possible to cross connect the encoders/scales? By this, I mean that you would hook the Y axis to the X axis and vice versa. If the problem follows the encoder/scale, then that would suggest the issue is with the encoder/scale.

...BUT....

Be aware that you would NOT want to take the machine out of E-Stop in this configuration. It very well might result in a runaway axis or other problem..... It could be a HORRIBLE idea so I would think through all of the ramifications BEFORE you attempt this. I am not a professional CNC technician and it is only an idea. If you decide to try this, you are making the decision entirely on your own and you assume all of the risk and danger to yourself, anyone around you, and the machine!

[Nitin1310]

Hello, i have facing same problem with my machine, controller give z71 0001 (x2z2), i tried with all swap like encoder cable, drive but still controller given same alarm z71 0001 (x2z2), change drive with rotary switch setting.

There is combi drive MDSDMV3-404040

CONTROLLER is M700


I hope you find some solution, then please share it

[MrMetric]

These controls are new enough that I would think Mitsubishi support may be willing to give you a quick (free) suggestion on where you should look. If the issue was on a 1990's vintage M3xx or M5xx control, they may not have as good knowledge now. Unfortunately I'm better with the older stuff than the new, and even there, I'm definitely not a trained service tech! Best of luck though in your search, and I would like to encourage you to post your results here so that others can benefit.