MELDAS 520AMR, What does the different memories do?

[CNC Viking]

Hi, all MELDAS experts out there!


My NC-specs says that I have the following memory components on my CPU module:

QX424A: 1 MB SRAM memory on the CPU main board.

QX812A: 256 KB ROM User PLC Cassette memory RH cassette location

QX635A: 2 MB ROM Main Cassette memory LH Cassette location

I have some questions about these:

1. What exactly does each of them contain, buffer, etc.

2. Which memory is used when Drip Feeding a program from a PC to the NC?

3. Where are the machine parameters stored?

4. Where are the Tool Parameters stored?

5. Where are the Fixed (Canned) Cycles stored.

6. Where are the User machining programs stored?

[peter pan]

As with all MELDAS 500-series controls, LH and RH cassettes are both flash ROM's. LH cassette contains the system software (interpolation algorithms, G-code compiler, etc). During a software update, the data can be re-written. However, this is rarely done and usually not necessary. The RH cassette contains user PLC program in ladder and/or C-language as well as possibly some macros created by the machine builder. This data can also be overwritten with special knowledge and equipment. Normally, only the machine builder would be doing this.

User programs, tool data, all parameters (system, machine, user) all reside in the S-RAM (QX-424 on the CPU board) and are backed up by battery. The machine parameters and system parameters are automatically backed up to the EEPROM on the CPU board every time you power off. Canned Cycles reside in the S-RAM also, but a master copy of these is included in the system software. If you get a flat battery and lose the S-RAM memory contents, you can reload the canned cycles from the LH cassette whilst the machine and system parameters will automatically restore themselves from EEPROM. The NC type and serial number are also stored on the EEPROM (which is a removable chip on the CPU board).

Regarding memory used for dripfeeding, I would guess that this is a function of the D-RAM (dynamic RAM) which also resides on the CPU board. This is like "RAM" found in a standard PC which means it only stores data whilst NC power is on.

Hope this helps.

[CNC Viking]

Thanks for the very thorough answer,

So it is possible to remove most of the common user programs from the S-RAM, store them in the PC instead and thus increase the canned cycle space in the S-RAM?

Do you know the size of the D-RAM in a 500-series?


EDIT, added re. Tape Mode / Drip Feed Mode:

In the Mitsubishi Manual BNP-B2036, MELDAS 520A series Maintenance Manual (Hardware Section), I found this information on page 61. I did not know it also use a memory in the CRTC module for this, let alone that there even was another QX424 S-RAM.


So how will this handle a + 50 000-line modern 3-d program off a CAM-software.

[memoryman]

Just to add: the 520AMR cannot have more than 320 m/128k of part program storage. That model was for export only with limited functionality.

[CNC Viking]

My typical bad luck!
What else is missing compared to a standard 520AM?

Can you list the features of each and the available options?

At least I have the "expanded" 256 kB memory and Synchro Tap options. And I have quite a few of the "optional" canned cycles.

[onthebumper]

It is possible to go to 1200m/480k of memory with some hardware change. The 500A controls definitely have lower functionality but I am unsure of every function that is unavailable.

[memoryman]

I don't know what other features are missing. We have been designing expanded memory for the 500 series and have a good amount of knowledge.
The CPU and display boards are unique to the AMR. We do have parts for the Mits controls.
Bill

[CNC Viking]

memoryman,

I do not think I will require bigger memory, since I will drip feed all my machining from a PC. I have removed all stored NC programs from the CNC and have only the canned cycles and a tool length measuring macro left in there.

A 1MB or 2MB memory will not help much anyway, if I run a 3D-program with 50 000 - 100 000 lines in it.

BTW, do you know what the "R" means in 520AMR?

memoryman, onthebumper,
If any more facts about these controls come to mind, please do share them here. Thanks.

I am glad that the 500 series is still going strong, and that there are people like you out there that take the time and effort to help the less experienced with these controls.

[onthebumper]

The R means it has a 9" crt.

If you are drip feeding the control then eliminating programs from the control will not help. A standard drip feed does not use the memory in the control as a buffer and if you are doing Mold parts or something like it you may not like the results. You might want to test it first.

I know Mitsubishi has some options for adding a buffer on the standard 500 controls but I am unsure if they are available on a 520A control. Maybe a good idea to give them a call to see if they have some thing or just test the machine, maybe what you have will work fine.

Here is a procedure Mitsubishi has on drip feeding to your control http://www.meau.com/functions/dms/ge...00000472800000

[CNC Viking]

I know that the User PLC ROM is not used during drip feeding. I just emptied it anyway since I want to have the programs in one place only, the PC. Maybe I can use the surplus place in the ROM for more macros, canned cycles etc.

Thanks for the link, but I use Tape mode sucessfully already via SDS as well as regular RS232. It seems I get away with running 3D-programs at 19 200 Baud with both methods.

Anyway, there must be a buffering RAM somewhere that is used for the MDI mode and for drip feeding (Tape mode). I am curious how big that one can be. When drip feeding, I see that the DNC program show frequent changes between RTS and CTS all the time, so that RAM can't be big. And where is it located?

[onthebumper]

I'm not sure where the RAM for drip feeding is located or how big it is but I've always been told that it is very small as you have seen and that is why Mitsubishi offered options like computer link that added boards to the control with additional RAM for a buffer. I've been told it works quite well but I've never seen it in action.
The MDI program is stored on the Main SRAM board QX423 and I do not believe it shares memory with the drip feeding/tape mode function.