Mori Fanuc 2000 C, Battery Alarm: Parity 16578

[Vince4]

I am running into this problem avery time I start the unit. Could anyone provide with some reference to the error code? I have no manual on hand.

Thanks in advance

[Dan Fritz]

The parity alarm is saying that the controls CPU has read some bad data (data with the wrong number of bits) from a memory chip at hex address 40C2 This is the hex equivalent of the decimal number on your display.

The 2000C has two types of memory. The Executive program (the CNCs firmware) is saved in a bunch of Programmable Read Only Memory chips (PROMs) on the main memory board (slot #9). PROMs are not supposed to change because the data are "burned in", but if a PROM chip goes bad or gets loose in its socket, it can generate a parity alarm. The "volitile" memory that stores the part program data, the tool offsets, and the parameters uses a set of CMOS Static RAM chips. These chips require the battery backup, and they can throw a parity alarm if you let the battery run down. Obviously, your battery is low, and when you turn off the control the CMOS RAM chips don't have sufficient power to keep their data.

All 2000C controls have a small battery on the main memory board (slot #9) which backs up the parameter and offset data. This battery is about the size of 3 watch batteries stuck together, and it has two small wires attaching it to the board. SOME 2000C controls also have non-volitile part program memory, which is (I believe) the board in slot #10. This board may have a second battery (a larger battery pack, the size of 3 C cells). If you have to re-load your part program every time you turn the control off, then you don't have this type of part program memory board.

First of all, replace those batteries. You can fabricate your own as long as they are about +5v, or you can buy them from several Fanuc service centers online. If the parity alarm won't go away, you may need to erase the parameters and re-enter them. That procedure is in the Maintenance manual.

Second, turn off the control, then carefully pull out the memory board from slot #9, and press on each of the PROM chips to seat them firmly in their sockets. These chips tend to "wiggle" out of their sockets over many hot/cool cycles, and they start to loose contact. With all the PROMs firmly seated, insert the board back into the slot and plug/unplug it from the backplane several times to "wipe" the backplane contacts. You can also wipe the contacts of the CPU board in slot #8 if you like.

Hope this helps.

[Vince4]

Thanks Dan;

I will try your indications. and I let you know the result.

Vince

[Vince4]

Hello Dan
We followed your indications. However, we cannot find the maintenance manual, and now we are stuck trying to erase and re-enter the parameter. The problem might be that we are not using the proper procedure to erase and re-enter the parameters. Do you happen to have a copy of the procedure?
We have tried locating a maintenance manual unsuccessfully.
Thanks

[jackson]

have you changed the batteries some machines have batteries that is how they dont loose the memory if you change them change with the machine on or you will be typing in parm. by hand

[asuratman]

Hello Dan,
I have Mazak M4 with Fanuc C2000. All hydraulics are working (Tail stock, spindle chuck, etc). Machine is in ready mode. When I move left or right on panel control stick, display is changed but motor on all axis not move. Spindle can rotate. Parity error is 32528, everytime I enter data. Is there any parameter missing or what? Thanks. Aristo.

[Dan Fritz]

asuratman: Look for a panel switch marked "MLK". If it's on, turn it off. MLK means "Machine Lock", and it lets you run your program without moving any axes. MLK is the only signal I can think of that will let the display move without letting the axes move.

The parity alarm is probably a bad chip (or a chip with garbage data in it) on your "memory & edit" board. Try to clear your part program memory completely.

Some 2000C controls have a memory board that has a battery backup. If you have a battery pack that looks about the size of 3 "C" cells linked to gether, its probably the battery for the board in slot #10. This battery can be unplugged for a few minutes while the CNC is turned off, which clears the part program memory. After doing this, you'll have to "clear" the memory by erasing it (use the "program erase" procedure in the manual)

Beware that SOME controls are wired up so that the same battery backs up the parameters and tool offset data on the board in slot #9. Most 2000Cs have a separate parameter battery on the board in slot #9, so unplugging the part program memory battery won't dump your parameters. Better make sure that you have a list of the parameters before you unplug the battery, just in case.

You could also have a bad chip on the part program memory board. I'd still try to clear it before replacing any chips or boards.

Once the parity alarm happens, the CPU halts, so I'm assuming that you're trying to jog the machine BEFORE the parity alarm happens, no?

[Dan Fritz]

Answer for previous post by Vince4:

All the basic parameters can be entered into a 2000C by this procedure:

With the control turned on, turn on the toggle switch on the back of the MDI display board (the board with the LEDs on it). You'll have to open the control's door to see it. This toggle switch is marked "Parameter Write" (or something like that).

Put the control in MDI mode, then run the address LED under the letters "PRM". Next, enter the 2-digit number of the parameter, enter the "1s" and "0s" of the parameter, then press INPUT. Keep indexing the 2-digit number until parameters 00 through 20 are all in.

To enter parameter 21 and 22, you'll have to use this special procedure. These are the "option" parameters.

(1) Go to parameter 17 and enter this bit pattern: 1 0 1 0 0 0 (input)
(2) Go to parameter 21 and enter your data
(3) Go back to parameter 17 and enter 1 0 1 0 0 0 (input) again
(4) Go to parameter 22 and enter your data.

Remember to turn off that parameter toggle switch when you're done!


The 3000C is similar, but the option parameters are 27, 28, 29, and 30. The key code for entering the option parameter on the 3000C is in parameter 26, and the bit pattern is: 1 0 0 1 1 1


If you've lost the parameters on either a 2000C or 3000C, you can enter them all manually in just a few minutes, but remember that there is one additional memory register that you must enter: Run the address LED under the letters "SET" and you will see what looks like another parameter. The bits are for Inch/Metric, Mirror image (3000C only), ISO tape code, etc. If these bits are all zeros, you'll be in metric mode and the control will only be able to read EIA tapes (it can't read ASCII tapes unless you put a "1" in the "ISO" position)

[asuratman]

Thanks Dan,
I will try your recommendation. How many parameter on Fanuc 2000 C that should be entered. Asuratman.

[asuratman]

Hi,
I changed batteries, Machine Lock is off, now I got parity 16578 on my machine. Could it be a bad chip or need some more parameter. Please for any help. Thanks. Asuratman.

[Dan Fritz]

Your main memory board (slot #9 in the rack) has a bunch of plug-in PROM chips. Each chip is numbered. The address of your parity alarm (16578) translates to 40C2 Hex, which is in three chips (numbers 160, 164, and 168). You may want to pull the board out of it's slot and be sure that these 3 chips are fully seated in their sockets. Sometimes they wiggle loose from many hot & cold cycles. If you remove the chips from the sockets, be sure to plug them back in the EXACT SAME sockets, and be sure to not bend a pin.

Also be careful to not disturb the battery connections to that board. There is usually a small battery to back up the parameters with two wires that plug into the board, but some controls may have a cable to an external battery pack. Don't disconnect the battery from the board or you'll loose your parameters again.

Another thing to try is to simply plug & unplug that board from the backplane connectors a few times. Sometimes a bit of corrosion on the backplane connectors causes these parity alarms also. You might also do that with the CPU board in slot #8. A dirty backplane connector on either board can cause your parity alarm.

[asuratman]

Where to find for ROM replacement with this ID (SL41479 93436-DC F7721), legs been broken. Should I replace bpard? Thanks.