Starting FANUC Robots in AUTO

Filed under: FANUC

You’ve finished programming your robot, tested it in T1, and now you want to run it faster. If you’re like me, you sometimes forget the details on Remote vs. Local, UOP signals and the different startup types available (RSR, PNS, Style, Other). For your (and my own) reference, here’s a quick no-BS guide on how to get things running.

NOTE: If you like this post and are interested in the programming side of things, be sure to check out my book on programming FANUC robots.

The Mode Select (T1/T2/AUTO) Switch

T1 and T2 are for teaching and testing the robot. T1 limits the tool center point (TCP) speed to a nice and safe 250mm/sec.

If your robot has T2, you probably have an older robot or you’re outside the US. This mode became non-standard in the US several years ago, but it allows you to test-run programs with the teach pendant at full speed. Be careful out there.

When the robot is switched into AUTO, you’re running programs without the teach pendant. In fact, if the teach pendant is enabled, the robot will be in a fault condition. Some other device (covered later) will issue signals to start the robot.

Fence Circuit

The fence circuit is bypassed in T1 and T2, but it must be closed when in AUTO mode.

Local Mode

Now that your robot is in AUTO, you can choose to start it remotely or locally. This configuration option is on the System Config screen (Menu > System > Config).

When in local mode, the robot will be started from the Standard Operator Panel (SOP) buttons located on the controller.

Be careful: when the robot is in local mode, it will always run whatever program you have selected on the SELECT menu. The robot will ignore any setup you have done on the Program Select method screen.

I generally switch things over to AUTO/Local after some thorough testing in T1. Start out slow with your finger on the HOLD button, gradualling bumping up the override before doing the same thing with the PLC in charge.

Remote Mode

When the robot is in Remote mode, it will follow the Program Select method and Production Start method you defined in the system config screen. You’ll probably always use UOP as the Production Start method.

There are four Program Select methods: RSR, PNS, STYLE and OTHER, but I think OTHER is best option.


Ah, OTHER: the simplest, most barebones and easy-to-use startup method. The robot simply runs an explicitly stated program when it receives a start signal.

Set your Program Select Mode to OTHER on the system config screen and then specify a program to run by hitting DETAIL. You can also set the program name via the $shell_wrk.$cust_name system variable.

I find that keeping it simple, having the robot start some main task and handling any job requests, etc. from there is generally best, but I’ll briefly summarize the other methods as well.

Robot Service Request (RSR)

I’m not sure why anyone would use this program select method. (If you have a compelling reason, please let me know.) RSR basically lets you specify 8 numerically identified programs that correspond to 8 input bits. You have the option to add an acknowledge bit, but it’s not really a full handshake.

The setup screen has you associate a number with each of your 8 RSR bits (e.g. 10, 20, 30, etc.). You can also specify a base that these numbers will get added to (e.g. 100). With these example values, if the RSR1 input is given the robot will execute RSR0110 (base of 100 + RSR1 bit value of 10). RSR2 would execute RSR0120, RSR0130 for RSR3, and so on.

You have to follow this naming convention (RSRxxxx) exactly, but you can modify the RSR prefix via $shell_cfg.$job_root.

I’m not a fan of these non-descriptive names (what the heck does RSR0150 do again?), so I wouldn’t recommend using this method.

Program Number Select (PNS)

PNS is kinda like RSR, but it interprets the 8-bits as a binary number. You don’t have to explicitly set numbers fo each signal, but you can define a base number $shell_cfg.$pns_base. The naming convention is similar (PNSxxxx) unless you change the prefix with $shell_cfg.$pns_program.

This startup type is a bit more useful since it requires less setup and you get more jobs, but I’m still not seeing the benefit here…

Style Select

Style is basically PNS without a naming convention. You have to explicitly setup a table that associates a given TP program with the input job number.

Additionally, you can enable/disable entries via the setup table. You can also write a comment to remind yourself what your poorly named program does if that’s how you roll.

The bottom line with Program Select methods

It seems to me that the RSR, PNS and STYLE Program Select methods are all remnants of an earlier time. Who wants to name their programs RSR0001 or PNS1000 when you could write something more descriptive like UNLOAD_LATHE_A?

If you can’t be bothered to setup your own logic for job requests, STYLE is probably your best bet.

A simple job request handshake

Here’s how I might write a simple routine to get a job request:

LBL[1] ;
WAIT (DI[1:job request]) TIMEOUT,LBL[500] ;
R[1:job]=GI[1] ;
! GO[1:job] echos R[1] in BG logic ;
DO[1:job ack]=ON ;
LBL[2] ;
WAIT (!DI[1:job request]) TIMEOUT,LBL[501] ;
DO[1:job ack]=OFF ;
LBL[500] ;
! timed out waiting for job ;
JMP LBL[1] ;
LBL[501] ;
! timed out waiting for job request to go low ;
JMP LBL[2] ;

The PLC would be responsible for validating GO[1] after DO[1:job ack] comes on.

Then your main routine might look something like this:

LBL[1] ;
               =2,CALL SOME_OTHER_JOB ;
! maybe put a job done handler here ;
JMP LBL[1] ;

In 2016 I think it’s a little silly to pass integers around… I haven’t personally seen anyone do it this way, but you could (in theory) use Explicit Messaging to set a string register and call the result:

LBL[1] ;
! populate SR[1] ;
CALL SR[1] ;
! maybe put a job done handler here ;
JMP LBL[1] ;

UOP Signals

I’m willing to bet you’re going to start your robot with a PLC communicating via Ethernet/IP. I won’t go over the Ethernet/IP setup here (maybe a topic for another post), but let’s quickly cover the various UOP signals and what they do.

UOP Input Signals

On the input side (from the robot’s perspective), you get up to 18 signals, but you’ll probably only need the first 8.

NOTE: You have to enable UI signals from the MENU > System > Config screen. Set “Enable UI Signals” to TRUE.

UI[1:*IMSTP] Leave this on all the time. When it drops, the robot will stop immediately, but this should not be used for safety purposes.

UI[2:*Hold] Leave this on unless you want to pause the robot. If this signal ever dips, the robot will slow to a controlled stop, pause its program and wait for a start signal to resume.

UI[3:*SFSPD] This annoying little signal is normally on. When it drops, it will pause the robot and clamp the override to $scr.$sfrunovlim. If you’re in teach, it’ll clamp the override to $scr.$sfjogovlim.

UI[4:Cycle stop] This signal can be used as a cycle stop or immediate abort signal depending on the value of $shell_cfg.$use_abort. If set to true, it will act as an abort signal. If set to false, you’ll have to check UI[4] in your program and ABORT by hand.

UI[5:Fault reset] Normally off, this signal will attempt to reset any errors on your robot. Note: your robot cannot start or resume if any faults are present.

UI[6:Start] This one depends on $shell_cfg.$cont_only. If set to true, UI[6] will only resume a paused program, and you’ll have to use UI[18:Prod start] to start from scratch. If set to false, it will resume or start an aborted program from the cursor position.

UI[7:Home] Pretty useless, but the idea is that your robot will execute a home macro when this signal is received.

UI[8:Enable] When this signal is high, the robot can move.

So basically, to start the robot:

  1. Turn on UI[1:*IMSTP]
  2. Turn on UI[2:*Hold]
  3. Turn on UI[3:*SFSPD]
  4. Turn on UI[8:Enable]
  5. Pulse UI[5:Fault reset] to clear any faults
  6. If there are no faults, pulse UI[6:Start]

If the robot is paused (from dropping the hold signal, a fault or e-stop):

  1. Keep UI[1:*IMSTP], UI[2:*Hold], UI[3:*SFSPD] and UI[8:Enable] high
  2. Pulse UI[5:Fault reset] if necessary to clear faults
  3. Pulse UI[6:Start]

UOP Output Signals

You’ll get some signals back from the robot if you want. Feel free to use any or all of them to make your PLC more intelligent.

UO[1:Cmd enabled] This is ON when the robot is in Remote mode and not faulted. You can only start/resume the robot when this is ON.

UO[2:System ready] Servo motors are on

UO[3:Prg running] A program is running

UO[4:Prg paused] A program is paused

UO[5:Motion held] On when the robot is actively being held (e.g. UI[2:*Hold] is low)

UO[6:Fault] On when there is a fault that needs to be cleared/reset

UO[7:At perch] When the robot is at reference position #1

UO[8:TP Enabled] When the teach pendant is on

UO[9:Batt alarm] When the CMOS RAM battery voltage is less than 2.6V or robot battery voltage is low

UO[10:Busy] When the robot is thinking

I’m not a PLC guy, but I would:

  1. Make sure UO[1:Cmd enabled] is on before issuing any start signals
  2. Don’t bother issuing any start signals if UO[3:Prg running], UO[5:Motion held] or UO[6:Fault] is on
  3. Know that you’ll have to give a reset if UO[6:Fault] is on
  4. Maybe prohibit a start from the top unless `UO[7:At perch] is on
  5. Tell the operator to turn off the TP if you want to run and UO[8:TP enabled] is on
  6. Tell someone to change the batteries if UO[9:Batt alarm] is on

That about does it. At this point you should know how to start your robot both locally and remotely while in AUTO via whichever program select method serves you best. We also covered the UOP Startup Method which you’ll probably use 99% of the time. (The other option is OTHER, which looks at a system variable $shell_wrk.$cust_start, usually used when the robot is controlled by a PC.)

Let me know if you have any questions or know something about RSR/PNS/STYLE that I’m missing!

If you enjoyed this post and want to learn more about FANUC robot programming, please check out the book I wrote, Robot Whispering: The Unofficial Guide to Programming FANUC Robots.

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