1. FANUC Teach Pendant Basics: How to Navigate Without Getting Lost

June 25, 2026 JoeGuardian 0

Introduction

For many automation technicians, the first challenge with a FANUC robot is not the robot arm itself. The real challenge is the Teach Pendant.

When a robot stops in production, the pendant is where you will check alarms, see the active program, find the stopped line, check I/O signals, move the robot manually, and recover the cell safely.

This post is the first part of the FANUC Robot Technician Series, focused on practical plant-floor knowledge for technicians working with robots that pick, place, stack, palletize, or handle containers and boxes.

The goal is simple:

Learn how to use the FANUC Teach Pendant without getting lost.

1. What Is the FANUC Teach Pendant?

The Teach Pendant, also called the TP, is the handheld operator interface used to control, jog, program, troubleshoot, and recover a FANUC robot.

A typical FANUC robot system includes the robot arm, robot controller, teach pendant, end effector, safety fence or guarding, interlocked gates, I/O devices, and other peripheral equipment. FANUC safety documentation identifies the robot, controller, teach pendant, safety fence, interlocked gate, interlocking device, end effector, and workpieces as part of the overall robot system configuration.

In real plant terms, the pendant is where you go when:

The robot is in alarm.
The robot stopped mid-cycle.
You need to see what program is running.
You need to move the robot manually.
You need to check inputs and outputs.
You need to adjust a pick or place position.
You need to recover the robot after a jam, bad pick, or collision.

2. Main Things You Need to Know First

Before editing programs or touching positions, you should become comfortable with these basic areas:

Area	Why It Matters
Alarm Screen	Shows why the robot stopped
Program Screen	Shows what logic the robot is executing
Line Number	Shows exactly where the robot stopped
I/O Screen	Shows signals between robot, PLC, sensors, and gripper
Position Screen	Shows current robot position
Jog Controls	Allows manual movement
Coordinate System	Determines how the robot moves when jogging
Speed Override	Controls robot motion speed
Reset	Clears alarms after the real problem is corrected
Step Mode	Runs program one instruction at a time

This post is not about advanced programming yet. It is about building navigation confidence.

3. FANUC Operating Modes: AUTO, T1, and T2

FANUC robots commonly use operating modes such as AUTO, T1, and sometimes T2, depending on the controller, region, configuration, and safety design.

Mode	General Use
AUTO	Normal production operation
T1	Teach/manual mode, normally used for slow-speed jogging and testing
T2	Higher-speed test mode, available only on some systems
Remote / Local	Determines whether the robot is controlled from pendant, PLC, or external system

T1 is normally the mode technicians use when they need to enter Teach Mode and move the robot manually. FANUC-related safety material describes AUTO and teach modes such as T1/T2, and emphasizes selecting the correct mode before teaching or entering the guarded area.

In a production cell, AUTO usually means the PLC, HMI, or cell control system is controlling the robot sequence. T1 means the technician or programmer is using the pendant for manual movement, testing, or recovery.

4. The Most Important Pendant Buttons

Different pendant models may look slightly different, but the core concepts are similar.

Common Buttons and Functions

Button / Function	Purpose
RESET	Clears active alarms after the cause is corrected
SHIFT	Used with other keys for jogging and special actions
Deadman Switch	Enables motion in Teach Mode when held correctly
FWD	Runs the program forward, often used in step testing
BWD	Steps backward in some situations
STEP	Enables one-line-at-a-time execution
HOLD	Pauses robot execution
E-Stop	Emergency stop for unsafe conditions
COORD	Changes jog coordinate system
MENUS	Opens major menus
SELECT	Shows available robot programs
EDIT	Opens selected program for viewing or editing
DATA	Opens registers, position registers, and other data
I/O	Opens input/output screens
POSN	Shows current robot position

The deadman switch is a critical safety function. FANUC safety documentation describes the deadman switch as an enabling device used when the teach pendant is enabled; motion is allowed only while the switch is held in the correct position.

Important practical note:

If you release the deadman, the robot stops. If you squeeze it too hard, the robot may also stop. It usually has a middle “enabled” position.

5. First Skill: Reading the Alarm Screen

When the robot stops, do not start pressing RESET repeatedly.

First, read the alarm.

What to Look For

On the alarm screen, identify:

Alarm code
Alarm text
Active alarm or historical alarm
Time of alarm
Whether the same alarm returns after reset
Whether the alarm is safety, servo, motion, program, I/O, or system related

Typical alarm categories may include:

Alarm Type	Possible Meaning
SRVO	Servo, motion, safety, or axis-related issue
MOTN	Motion not allowed or motion error
INTP	Program/interpreter issue
SYST	System issue
TPIF	Teach pendant/interface issue
Safety Alarm	Gate, E-Stop, fence, scanner, enabling device
Collision Guard	Robot detected abnormal force or impact
Overtravel	Axis moved beyond allowed limit

Technician Rule

Do not reset blindly.

Use this order:

1. Read the exact alarm.
2. Identify the alarm type.
3. Check if the cause is still present.
4. Correct the real problem.
5. Then press RESET.

A robot alarm is information. Treat it like a PLC fault code or VFD fault code.

6. Second Skill: Finding the Active Program

When the robot stops, you need to know what program it was running.

Go to the program area and identify:

Program name
Current line number
Motion instruction
Wait instruction
I/O instruction
Called subprogram

A basic FANUC program may look like this:

1: UFRAME_NUM=1 ;
2: UTOOL_NUM=2 ;
3: J P[1] 50% FINE ;
4: L P[2] 500mm/sec CNT50 ;
5: DO[10]=ON ;
6: WAIT DI[5]=ON ;
7: L P[3] 250mm/sec FINE ;

What This Means

Line	Meaning
`UFRAME_NUM=1`	Active user frame
`UTOOL_NUM=2`	Active tool frame
`J P[1]`	Joint move to position P[1]
`L P[2]`	Linear move to position P[2]
`DO[10]=ON`	Turns on an output
`WAIT DI[5]=ON`	Waits for an input to turn on

If the robot is stopped on a WAIT DI[x]=ON, it may not be a robot problem. It may be waiting for a signal from the PLC, sensor, gripper, vacuum switch, or safety system.

7. Third Skill: Understanding the I/O Screen

For technicians, the I/O screen is extremely important.

A lot of “robot faults” are really missing signals.

Common Robot Inputs

These are signals coming into the robot:

Robot Input	Possible Meaning
Part Present	Box/container is ready
Gripper Opened	Tool is confirmed open
Gripper Closed	Tool is confirmed closed
Vacuum OK	Product is held
Safe To Pick	PLC says area is clear
Conveyor Ready	Conveyor is in position
Reset Request	PLC or HMI requests fault reset
Cycle Start	Start signal from PLC
Program Select	PLC selects robot program or recipe

Common Robot Outputs

These are signals leaving the robot:

Robot Output	Possible Meaning
Robot Ready	Robot is ready for cycle
Robot Running	Robot is executing
Robot Faulted	Robot has an active fault
Robot Home	Robot is at home position
Pick Complete	Pick operation completed
Place Complete	Place operation completed
Gripper Open Command	Command to open tool
Gripper Close Command	Command to close tool
Vacuum On	Command to activate vacuum

Practical Example

Robot stopped at:

WAIT DI[12]=ON

DI[12] could be:

DI[12] = Vacuum_OK

If Vacuum_OK is OFF, the robot may be waiting because:

Vacuum cup is damaged.
Air pressure is low.
Box is not sealed.
Vacuum sensor is misadjusted.
Solenoid did not energize.
Hose is leaking.
Product is not in the correct position.

The robot is not always the root cause. The pendant helps you prove what the robot is waiting for.

8. Fourth Skill: Checking Robot Position

The position screen shows where the robot currently is.

You may see values such as:

X = 1250.500
Y = 840.200
Z = 350.000
W = 180.000
P = 0.000
R = 90.000

Or joint values such as:

J1 = 10.000
J2 = -25.000
J3 = 40.000
J4 = 0.000
J5 = 90.000
J6 = 180.000

Cartesian Position

Cartesian position usually uses:

Axis	Meaning
X	Forward/back or cell direction depending on frame
Y	Left/right depending on frame
Z	Up/down depending on frame
W	Wrist rotation
P	Pitch
R	Roll

Joint Position

Joint position shows the angles of each robot axis:

Joint	Meaning
J1	Base rotation
J2	Shoulder
J3	Elbow
J4	Wrist rotation
J5	Wrist bend
J6	Tool rotation

For troubleshooting, joint position helps you understand the robot posture. Cartesian position helps when adjusting pick/place locations.

9. Fifth Skill: Jogging the Robot Safely

Jogging means manually moving the robot with the pendant.

Before jogging:

1. Confirm the cell is safe.
2. Use Teach Mode / T1.
3. Hold the deadman correctly.
4. Lower the speed override.
5. Know your coordinate system.
6. Move slowly.
7. Watch the tool, not only the robot arm.
8. Keep clear of pinch points.

Coordinate Systems

The pendant can jog in different coordinate modes.

Jog Mode	Meaning
Joint	Moves individual robot axes
World	Moves relative to the robot/world coordinate system
Tool	Moves relative to the tool direction
User	Moves relative to a defined work area or fixture
Jog Frame	Custom jogging frame on some systems

Practical Recommendation

For beginners:

Use Joint to get out of awkward positions.
Use World/User when you need simple X/Y/Z movement.
Be careful with Tool, because Z may follow the tool direction, not straight up/down in the cell.

10. Sixth Skill: Speed Override

The speed override controls how fast the robot moves.

When recovering from alarms or adjusting positions, use low speed.

Example:

Speed Override = 5% or 10%

Do not jog at high speed near:

Product
Conveyor
Gripper
Fence
Pallet
Stacker
Machine frame
Operators
Sensors
Air lines

A small movement at the wrong speed can cause a crash.

11. Seventh Skill: STEP Mode

STEP mode allows the technician to run the robot program one instruction at a time.

This is very useful after:

Alarm recovery
Position adjustment
Bad pick
Bad place
Jam recovery
Program troubleshooting

Why STEP Mode Matters

Instead of letting the robot run the full cycle, you can observe each instruction.

Example:

1: Move to approach
2: Open gripper
3: Move to pick
4: Close gripper
5: Wait for grip confirmation
6: Move up
7: Move to place

This helps you see exactly where the problem happens.

12. Common Beginner Mistakes

Mistake 1 — Pressing RESET Without Reading the Alarm

RESET does not fix the problem. It only clears the alarm if the condition is gone.

Mistake 2 — Moving in the Wrong Coordinate System

The robot may move in an unexpected direction if you are in Tool instead of World/User.

Mistake 3 — Editing a Position Without Writing Down the Original

Always record the original values before changing anything.

Mistake 4 — Confusing Program Fault With I/O Wait

If the robot is waiting for an input, the issue may be the PLC, sensor, gripper, or pneumatic system.

Mistake 5 — Testing in AUTO Too Soon

After recovery or position changes, test slowly in Teach/STEP mode first.

13. Basic Pendant Navigation Checklist

Use this when you approach a stopped robot.

1. Check if the area is safe.
2. Look at the pendant alarm screen.
3. Write down the alarm code and message.
4. Check the active program.
5. Check the current line number.
6. Identify if the robot stopped on a motion, WAIT, CALL, or I/O instruction.
7. Check relevant DI/DO signals.
8. Check gripper, vacuum, air pressure, and product position.
9. Reset only after correcting the cause.
10. Jog slowly if manual recovery is required.
11. Use STEP mode before returning to AUTO.

14. Real Plant Example: Robot Waiting for Box Confirmation

Situation:

The robot picks a box from a conveyor, but the cycle stops before picking.

On the pendant, the program shows:

WAIT DI[20]=ON

DI[20] is labeled:

Box_In_Position

The signal is OFF.

Possible causes:

Photo eye is dirty.
Box is not fully against the stop.
Conveyor did not index.
PLC did not send the ready signal.
Sensor cable is damaged.
Input mapping is wrong.
Mechanical guide is misaligned.

Correct troubleshooting path:

1. Check DI[20] on robot pendant.
2. Check the physical sensor.
3. Check sensor LED.
4. Check PLC input.
5. Check conveyor position.
6. Check box alignment.
7. Correct the cause.
8. Reset and test in STEP.

This is how a technician avoids guessing.

15. What You Should Practice First

Before changing any positions, practice these pendant navigation tasks:

1. Open the alarm screen.
2. Find the active alarm.
3. Open the program list.
4. Find the active program.
5. Find the current line.
6. Open the I/O screen.
7. Search DI and DO signals.
8. Open the position screen.
9. Change jog coordinate mode.
10. Change speed override.
11. Enable STEP mode.
12. Jog slowly in Joint mode.
13. Jog slowly in World or User mode.

The goal is not to become a programmer on day one. The goal is to stop being lost when the robot stops.

Conclusion

The FANUC Teach Pendant is the technician’s main tool for robot troubleshooting.

If you learn how to navigate the pendant, you can quickly answer the most important questions during downtime:

What alarm is active?
What program was running?
What line stopped?
Is the robot waiting for a signal?
Is the problem robot, PLC, sensor, gripper, air, or product position?
Can the robot be recovered safely?

Before learning advanced programming, master the basics:

Alarm → Program → Line → I/O → Position → Jog → STEP → Recover

That sequence alone can solve many real production problems.

JoeGuardian Automation