FANUC Program Transfer and Backup: RS-232, Memory Card, USB and DNC

Estimated reading time: 7 minutes

What Will You Learn in This Lesson?

In this lesson you will learn:

the data input/output logic on a FANUC control,
the I/O Channel selection,
the RS-232 connection,
the use of Memory Card/CF and USB,
the READ and PUNCH operations,
how DNC operation works,
how to send programs out and take them into the control memory,
how to back up programs, offsets and operator level data.

Parameter, PMC, SRAM and BOOT SYSTEM backups are outside the scope of this lesson.

The Basic Logic of FANUC Data Transfer

There are two directions in data transfer:

Output from the CNC to external media: sending a program or data from the CNC memory to a computer, a card or a USB memory
Input from external media to the CNC: taking a program or data from an external device into the CNC memory

These operations may be shown under different names on FANUC screens:

READ: taking data from external media into the CNC
PUNCH: sending data from the CNC to external media
INPUT: data input
OUTPUT: data output
F INPUT: file input
F OUTPUT: file output
IMPORT/EXPORT: expressions that may be used on newer control series

The term PUNCH is left over from the old punched tape systems. Even though no physical tape is punched today, it may still be used in FANUC documentation to mean data output.

Transfer Media That Can Be Used

Depending on the FANUC control series and its options, one or more of the following methods may be available:

RS-232 serial connection
Memory Card
CF card and a PCMCIA adapter
USB memory
Ethernet or a network connection
An external DNC system

Not every FANUC control has all the methods. For example RS-232 is more common on older FANUC 0-T and 0-M controls, while the Memory Card option may be seen on the 16/18/21 and 0i series. On newer FANUC 0i-F class controls, USB or network options may be available.

The presence of a connection slot on the panel does not mean that the related function is active and configured.

Checks to Make Before Transfer

Before a normal program transfer:

Verify that the machine is not in automatic operation.
Select the correct operating mode.
Determine the direction of transfer.
Verify the I/O device to be used.
Check whether there is enough free space in the CNC memory.
Examine the O program numbers to be transferred.
Check whether the same O number already exists in the CNC memory.
Back up the existing programs.
Verify that the card or the USB memory is recognised by the control.
Do not remove the media or cut the power during the transfer.

Caution: the name of the external file and the O program number inside the file may be different. The FANUC control mostly recognises the program from the O number in the content, not from the file name.

What Is the I/O Channel?

The I/O Channel is the selection that determines which connection the control will use for data input/output.

Depending on the control, different channels may represent:

the RS-232 connection ports,
the Memory Card,
the USB memory,
Ethernet or another external device.

The I/O Channel is generally seen on the SETTING, ALL I/O or data input/output screen.

The meaning of the channel numbers is not the same on every FANUC series. General tables found on the internet saying “this channel is USB” should not be used without verification.

The operator should:

record the current I/O Channel value,
check the data transfer instruction of the machine,
select only the channel they are authorised for,
return to the previous channel at the end of the operation if necessary.

Changing the I/O Channel should not require enabling PWE or changing service parameters. If a parameter intervention is needed for the connection, the work should be left to maintenance or service personnel.

Program Transfer with RS-232

RS-232 is the serial communication method found on many old and new FANUC controls.

The connection may consist of the following components:

the serial port on the FANUC control,
a suitable connection cable,
the serial port of the computer or a suitable converter,
DNC/program transfer software.

For the communication to work, the settings on both sides must match:

Baud rate
Data bits
Stop bits
Parity
Flow control
The port used
The file sending format

If one of these settings is different, the transfer may not start, may be cut off halfway, or character errors may occur.

Points to watch when using RS-232

Do not use a random cable or pin connection.
Use a cable that suits the electrical and connection diagram of the machine.
Verify the connection procedure from the builder’s manual.
Do not disconnect the cable during the transfer.
Check the file as text on the computer before taking it into the CNC.
Do not use unsupported special characters.
Examine the program again on the CNC screen after the first transfer.

If the RS-232 connection parameters have to be changed, the existing values should be recorded and the work should be carried out by authorised personnel.

Memory Card and CF Card

A Memory Card slot may be present on FANUC 16/18/21 and many 0i controls. On some systems a CF card is used with a PCMCIA adapter and appears on the screen as MEM CARD or CARD.

In general, using a Memory Card gives the following advantages:

It does not require a cable.
More than one program can be carried.
Programs can be stored on the card.
On suitable controls, DNC operation from the card is possible.

When using a card:

The card and file system supported by the control should be used.
It should be inserted into the slot in the correct orientation.
No forcing operation should be carried out before the CNC recognises the card.
The card should not be removed while data is being read or written.
The lock and write protection state of the card should be checked.
A separate backup of the files on the card should be kept on a computer.

A CF card and an SD card are not the same medium. A card or adapter that does not fit physically should not be forced.

USB Memory

USB support may be present on newer FANUC controls. Some controls use the USB memory only for file transfer, while others may also support different operations.

General use:

A compatible USB memory is inserted.
USB is selected from the file or device screen.
The folder and file list is opened.
The input or output operation is determined.
The file name and the O program number are checked.
The USB memory is not removed until the transfer is complete.

Not every USB memory may be recognised by an older control. The capacity of the memory, the formatting type and the file names can affect compatibility.

If the USB device is not seen, the operation manual of the control should be examined instead of randomly changing service parameters.

Sending a Program from the CNC

The general FANUC logic for sending a program in the CNC memory to external media is as follows:

Verify that the machine has stopped.
Generally select EDIT mode.
Open the PROG screen.
Go to the OPRT, I/O, ALL I/O or file menu.
Verify the output device.
Select the O program to be sent.
Start the PUNCH, OUTPUT or F OUTPUT operation.
Wait for the message showing that the transfer is complete.
Verify that the file has been created on the external media.
Open the file and check the beginning and the end of the program.

There may be different output options for a single program, a selected group of programs or all user programs.

At beginner level, bulk output or bulk delete commands should not be used from memory. The name of the operation on the screen and the scope of the selected programs should be read.

Taking a Program into the CNC from External Media

The general order of operation for taking a program into the CNC memory:

Keep the backup of the external file.
Check the O program number inside the file.
Search for the same O number in the CNC memory.
If it exists, export the current program instead of deleting it straight away.
Generally select EDIT mode.
Open the PROG and data input/output screen.
Select the correct I/O device.
Determine the file or the program.
Start the READ, INPUT or F INPUT operation.
Check the CNC program list after the transfer is complete.
Verify the program content from beginning to end.
Apply graphics and a controlled trial before running the program.

If the same O number exists in the memory, the control may:

give an alarm,
reject the input,
overwrite the existing program depending on the setting.

What this behaviour will be should not be assumed. An overwrite should not be carried out before the existing program has been backed up.

Why Should the File Content Be Checked?

The transfer giving a “complete” message does not mean the program is ready for production.

The following should be checked:

Is the O program number correct?
Is the beginning of the program complete?
Is there a suitable ending at the end of the program?
Have all the blocks been transferred?
Is there an unsupported character?
Have the decimal points been preserved?
Have the subprograms been transferred as well?
Do the O numbers called by the main program exist in the memory?
Are the M codes suitable for this machine?
Is the G code system compatible with the control?

A program taken from another FANUC control should not be accepted as directly compatible just because the brand is the same.

What Is DNC?

DNC allows a large program, or a program held on an external system, to be executed without being saved completely into the CNC memory.

On the FANUC panel the DNC operating mode may be seen under the following names:

DNC
TAPE
RMT
REMOTE
DNC OPERATION

The program blocks are sent to the control unit in order from an external source such as a computer, a network system or a Memory Card.

DNC can be used in the following situations:

if the program does not fit into the CNC memory,
if the program is managed on a central system,
if large mould or surface programs are being run.

Points to watch when using DNC

If the connection is lost, program execution may stop.
The computer going to sleep or the software closing can interrupt the transfer.
The file should not be changed while it is running.
The correct file and start position should be verified before Cycle Start.
Program restart may be different from a normal memory program.
Single Block and restart behaviour may differ according to the DNC system used.
The operator should also follow the transfer status of the external system.

DNC is not a normal program copying operation. It is the execution of the program from an external source.

Program Backup

A healthy program backup is not just a copy program sitting in the CNC memory. The backup should be kept on a medium independent of the control unit.

A suggested layout:

Machine name or number
FANUC control model
Backup date
Program number
Program description
Revision information

Backups can be kept:

on a computer,
on a company server,
in secure external storage,
with version and date information.

In a good backup practice:

It is checked that the file has been created.
It is verified that the file size is not zero.
The file is opened as text.
The first and last program blocks are examined.
The O program number is verified.
It is checked that the subprograms have been taken as well.
More than one independent copy is kept.

Backing Up Offsets and Operator Data

In FANUC maintenance and operator manuals, some data other than programs can also be transferred with the input/output operations.

As far as the control supports it, the data that can be backed up at operator level is:

Lathe Geometry Offset values
Lathe Wear Offset values
Milling Tool Length Offset values
Cutter Radius Offset values
G54-G59 Work Offset values
Operator level setting data

These operations can be carried out from the ALL I/O, OFFSET, WORK or the relevant data output screen.

The backed-up offset file may look like text in a program-like format. Before the file is edited by hand, its format and data units should be fully understood.

When restoring offsets

It should be verified which machine the file was taken from.
Lathe and milling offsets should not be mixed up.
The control model and the offset memory structure should be compatible.
A backup of the existing values should be taken.
The Geometry, Wear, H, D and Work Offset tables should be checked separately.
Production should not be started directly after the restore.

Since offsets depend on the machine, the tool setup and the workpiece, the offset file of another machine should not be used directly.

Service Backups Not Covered in This Lesson

The following operations are outside beginner operator training:

CNC parameter backup and restore
PMC parameters and Ladder
Full SRAM backup
BOOT SYSTEM operations
Servo and spindle parameters
APZ/APC and reference data
System software or card replacement
Unlocking protected builder macros
Changing the 9000 series protected program settings

If a protected program does not allow output, do not try to bypass the program protection or the service parameters.

First Checks When Transfer Fails

If the program transfer does not start or is cut off halfway:

Is the correct I/O Channel selected?
Is the correct device seen?
Is the CNC in the correct operating mode?
Are the external file name and the O number suitable?
Is there free space in the CNC memory?
Does the same O number already exist?
Is the card or the USB write protected?
Do the RS-232 settings match on both sides?
Are the cable and the connection correct?
Is there a reader/puncher or I/O alarm on the screen?

The alarm number should be recorded and verified from the relevant FANUC manual. Parameters should not be changed at random.

FANUC Note

On older controls such as FANUC 0-T and 0-M, program transfer is largely carried out over RS-232. On the FANUC 16/18/21 and 0i-B/0i-C series a Memory Card is often seen. On newer FANUC 0i-F and similar controls, USB or network functions may be available.

However, the connection options depend not only on the control series but also on the options purchased and the configuration of the machine tool builder.

Short Summary

READ means data transfer from external media into the CNC, PUNCH from the CNC to external media.
The I/O Channel determines the data input/output device to be used.
The meaning of the channel numbers is not the same on all FANUC controls.
The RS-232 settings must match on the CNC and on the computer.
Memory Card/CF and USB are not the same medium.
The card or USB should not be removed during a transfer.
The external file name and the O number inside the file may be different.
The existing program should be backed up before the same O number is overwritten.
DNC executes the program from an external source without saving it completely into the CNC memory.
Programs, offsets and operator data can be backed up separately.
Parameter, PMC, SRAM and BOOT SYSTEM operations are at service level.

Test Yourself

What are the data directions of the READ and PUNCH operations?
What does the I/O Channel determine?
Why should channel numbers not be selected from a general table found on the internet?
Which settings must match for an RS-232 transfer?
What is the difference between the file name and the O program number?
If the same O number exists in the memory, what should be done before taking the program in?
Why should the card not be removed during data transfer when using a Memory Card?
What is the difference between DNC and normal program transfer?
Why should the program content be checked again after the transfer is complete?
Which offset data can be backed up at operator level?
Why is a copy program in the CNC memory not considered an independent backup?
Which backup operations should be left to maintenance or service personnel?