BMC-40

[ab@dodds]

I get a "Leadscrew Map Checksum Failed; Data Was Invalid And Erased" at power up. Any ideas on what would cause this?

[fasto]

The batteries in the Dallas SRAM have died. Search this forum (Hurco forum) for "Dallas" and you'll find some threads on why this happens, and how to fix it.

The solution is to remove the Dallas SRAM chips, replace them with regular SRAM chips, solder in three 3.6V lithium batteries on the memory board, and install three jumper caps.

This thread => Click
seems to have a pretty good discussion.

[ab@dodds]

I was able to get the leadscrew data stored to disk. I have the info on how to change the Dallas chips, as well as the battery info. Is the anything else I need to do before I pull that board? The machine is a 1994 I believe with Ultimax II controls.

[fasto]

All this is from memory . I won't have a chance to check with the machine until later tonight.

If you have stored programs in the memory you need to save those as well. I save mine from the serial port, my floppy drive is not very reliable.

If you just now saved the leadscrew map from the machine to the floppy the saved map is probably corrupted, too - unless you had a saved copy from before.

You can do <enter> 100 <enter> from the first screen which will show the axis travels and any rotary axis setup, the homing position, and something else I can't remember.

You'll need the toolchange height: you can get at this from the manual screen. With the servo power ON, press <enter> 488 <enter> which shows the Z height for toolchanges. Write it down.

I can't think of any other parameters that need to be saved.

Afterwards:

I think the machine will need to be told its travels and homing position. I've not had to do this; there are some posts on the forum about how to do this. I think it's done from the <enter> 999 <enter> screen. When the machine is first turned on after the swap, the memory will be blank and you'll probably need to use <enter> 999 <enter> to get it started. Then it will reboot, and you can use <enter> 100 <enter> to set those items you wrote down before.

Don't do an auto toolchange until you reset the toolchange Z height. This was blank on my machine, so I had to figure it out from scratch. What I did to set mine was to turn the air off and jump the air pressure switch so the machine thought the air was OK (need air pressure to turn the servos on). Then I jogged Z to the toolchange height, and pulled the toolchanger back & forth by hand until I was satisfied that it was correct. I figured it'd be less chance for a crash that way.

You can load your saved programs back in. Should be all set.

[ab@dodds]

I was able to do <eneter> 100 <enter, and get the info on that screen. it does not show the homing position. It has ATC mag count, travels, calibrate direction, motor speed, spindle speed, & ATC type. I could not get the tool change height. I was able to find the <eneter> 488 <enter> screen through the machine diagnostic screen, but for the height it just has *******. I was not able to get to a <enter> 999 <enter> screen. It has been a real pain to get anything off this machine just because after a short period of time from power-up the screen goes blank except for the cursor. So I've been trying to move fast. Wondering if I haven't already lost the data I am looking for. There was a disk in a folder from Hurco in the electrical cabinet, hoping maybe that will have everything I need on it.

[fasto]

You've got about everything that you need. If the toolchange height is ***** that means the value was lost, so you'll have to figure it out like I did. It's no big deal.

The <enter> 999 <enter> is used if the memory has gotten so corrupt the machine won't start at all. It just stays on the first screen. This will happen when you replace the SRAM chips & batteries, <enter> 999 <enter> resets the memory to its defaults. Then you do <enter> 100 <enter> and put in the values you wrote down.

One of the secret screens which is <enter> 642 <enter> at the toolchanger diagnostic screen (where you found the <enter> 488 <enter> Z toolchange height), lets you edit the leadscrew map. If it's corrupted there's nothing to do except set it all 0's in both directions (you'll see what I mean when you get the screen up - there are softkeys for X+ X- Y+ and Y-). Most of us are running with a leadscrew map of all 0's because the leadscrew map got lost along the way. You can reconstruct the leadscrew map with a tenths indicator and a lot of patience.

If you have the Hurco disk it might have the leadscrew map on it, if the disk works.

All this assumes Ultimax V8.60 which you probably have. Older versions don't have the leadscrew map I don't think.

All the other settings are made with dip switches on the CRP board or the axis board.

[ab@dodds]

Thanks for your help thus far Fasto, it has been greatly appreciated. I was wondering if you might have some insight on something else. The owner has instructed the machinist to turn off that machine every night to help reduce our energy usage. Doesn't seem to be the best idea to me. We seem to be having issues more often now. Do you know anything about this?

[fasto]

The owner has instructed the machinist to turn off that machine every night to help reduce our energy usage. Doesn't seem to be the best idea to me. We seem to be having issues more often now. Do you know anything about this?

You're most welcome on the help - I'm sure after the fix there will be some more minor issues.

About shutting the machine off at the disconnect. I only use my machine a couple days a week at the most, so I shut it off when I'm done. I figure that it's really old (I have 36,000 hours on it). Some parts like the CRT tubes and CRT flyback supplies are probably at the end of their life. The capacitors in the power supplies, too. Why would I want these using up their remaining hours of lifetime while I'm not using the machine?

On the other hand, you can leave it in emergency stop with the disconnect switch on. This keeps the power on to the CRT tubes and the computer, while shutting the servos off. Most places that use the machines every day seem to do this. They only shut off the disconnect if they're going to be away for the week. This strategy keeps the temperature in the electrical cabinets even so there's no condensation which can be a real problem.
I bet the machine draws 1 or 2 kW or even more while it's sitting with the power on and the emergency stop pressed. If the machine is worked 40 hours a week, there's 128 hours that it's idle. That's like 250kWH or more of power used for no gain, so I can understand the owner's point too. Especially if he's got dozens of machines it adds up fast!

I suppose that I don't have a recomendation. I'd keep a notebook of the troubles that crop up, and if there are a lot more than before then leaving it on is the best idea.