My Programs Won't Fit Into Memory

Rybett Controls WebDoc 107   (Copyright 2008)   Return to [Index]

As Computer Aided Manufacturing becomes more sophisticated, the generated g-code programs become larger and larger. Mold makers routinely deal with megabyte files. Assuming you do not wish to divide programs into smaller sub-programs, there are only 2 options: increase CNC/BTR memory or dripfeed from a DNC computer.


Within limits, you can usually add to CNC or BTR memory. Contact your suppliers for specific data and prices. For Rybett Camstore 1/2 and Numeritronix Exec BTR interfaces, memory may be added in 200, 400 and 600 foot increments at a price of $100 plus $1/foot.

        200 feet (24K bytes) costs $300
        400 feet (48K bytes) costs $500
        600 feet (72K bytes) costs $700.

All Rybett Camstore 1/2 and Numeritronix Exec BTR units are built on an AX10 CPU mothercard which can support 2 daughter cards plugged onto long pins. All units have at least one daughter card. The additional memory becomes the second daughter card. If a second card already exists, it may be traded-in for credit at $1/foot to make room for the new card. Please give the part number of all daughter cards in your unit when ordering additional memory. Also, please indicate the number of RAM memory chips actually stuffed on these cards as some may be incompletely filled. For example:

AX70 32 chips in 4 rows 50 feet ( 6K bytes)

AX75 16 chips in 2 rows 100 feet (12K bytes)
           32 chips in 4 rows 200 feet (24K bytes)

AX155  8 chips in 1 row 200 feet (24K bytes)
            16 chips in 2 rows 400 feet (48K bytes)
            24 chips in 3 rows 600 feet (72K bytes)
            32 chips in 4 rows 800 feet (96K bytes)

AX131 16 chips + RS232/20mA 100 feet (12K bytes)

AX161 16 chips + RS422 only 100 feet (12K bytes)

AX186 16 chips + RS232/422 100 feet (12K bytes)


All Rybett BTR interfaces may be dripfeed from Rybett DNC software. This will present the NC control with tapes of nearly unlimited length. Almost all NC controls can run from the tape reader port, solving the memory problem. (A few controls, such as Fanuc 3 can use the tape reader only to load CNC memory. If this is the case, you can only add to or alter the Fanuc memory; dripfeed will not help.)

To setup Rybett DNC software to dripfeed a Camstore or Exec BTR, use the "-L" loop option on the Machine Setup page as follows:

For Exec 1501/2 (Rev N) use CAM2 driver and -L as download option.
For Camstore 1,2 or COM use CAM2 driver and -L as download option.
For Camstore 1SX or LPT use LPTBTR driver and -L among the "dash" options.

Some newer CNC controls may be dripfed from the serial RS232 port. In these cases, BTR hardware is unnecessary and only dripfeed software is required. Controls such as the Fanuc 10 thru 18, Fanuc 0 and 04PC fall into this category. To dripfeed newer Fanuc CNC controls, you generally set the I/O DEVICE to point to the serial port, then select AUTO and TAPE modes on the control and press CYCLE START. (On some Fanuc Model 0 controls used as retrofits, we have found the TAPE/DNC button to be unmarked but located next to ALARM.)

The older Fanuc 6B control usually comes with a serial port for loading memory. However, it cannot be dripfed without a BTR except in the special case of a remote buffer option. This option requires Fanuc board #A16B-1200-0270. If you already have this board, you can dripfeed the control. If you don't, it is easier to install a BTR.