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Robotics FAQ

Below you'll find information on more most frequently asked questions.

Click on a topic below to view the details:

SRVO - 062 / BZAL BATTERY ZERO

Background: 
This alarm can occur if the 4 D-Cell Alkaline batteries, in the mechanical unit, drain below 4.5 volts or if the pulse encoder cable is removed from the encoder cap.
Solutions: 

Recover is a three step process:

  • The alarm needs to be "unlatched", which is accomplished by going to the MASTER/CAL screen and pressing F3 [res_pca]. This command fires an unlatch pulse to all the encoders. Turn OFF and Turn ON the controller, so that it may re-boot with the encoder alarms "unlatched". If the controller is successful at unlatching the alarms, it will be replaced by a new error message "SRVO - 075 Pulse not established".
  • You will need to jog each robot axis about 10 degrees to insure that the "Revolution Marker Pulse" passes by each encoders' pulse detectors. Once the jogging is complete, pressing the RESET button should clear the SRVO - 075 alarm.
  • The robot will need to be "mastered" and "calibrated".

How do we avoid this problem from occurring in the future? The batteries should be replaced as part of Preventive Maintenance procedures as described in the Preventive Maintenance sections of the manuals provided with the robot.

SRVO - 027 / ROBOT NOT MASTERED

Background: 
This alarm can occur under several different scenarios, but the main ones are a) after a battery zero alarm, b) after a software re-load, or c) when the robot collides with something.
Solutions: 

The most common recovery method is to "Zero Position Master" the robot. Each axis has alignment marks. By jogging each axis in joint mode, so that these "witness marks" line up, you have placed the robot into "ZERO POSITION". Go to the MASTER/CAL screen and select "Zero Position Master", then select "Calibrate". For more accurate mastering, please refer to the data sheets provided with the robot for the original mastering data, and jog the robot to these positions rather than the alignment marks.

SRVO - 021 /SERVO READY OFF

Background: 
This alarm indicates either a problem with emergency stop circuits or with the servo amplifier. The amplifier powered-up as commanded, but it then powered-down without a recognized command from the axis control PCB.
Solutions: 

Some things to check are the correct functions of the door interlock switch, the E-Stop PCB, the Teach Pendant and/or the Teach Pendant Cable, Servo Amplifiers, or the Operator Panel Cable on an RJ2 or RJ3 controller. Power-down the controller and replace the suspected failed component as described in the Electrical Maintenance and Troubleshooting manual.

How do we avoid this problem from occurring in the future? During regular preventive maintenance procedures, inspect robot and controller components for damaged cable insulation and/or excessive twisting, controller door alignment and switch function, etc. and replace excessively worn or damaged components. If the failure has occurred, then the failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.

SRVO - 023/024 STOP/MOVE ERROR EXCESS

Background: 
These two alarms are two sides of the same coin so to speak. They refer to positioning errors either a) at rest (stop error) or b) during motion (move error). Stop errors can be caused by worn or slipping brake pads in the motors or a cable that has been damaged to the point that current from another axis is shorting to an axis that is supposed to be stopped. Move errors can be caused by failing amplifiers, cables, motors, or brakes that fail to release as commanded. Both alarms can be caused by a failed Axis Control PCB.
Solutions: 

Cable wear or damage can be a frequent cause of this alarm, but cables can be difficult to replace. It is best to visually check for cable damage and/or check the cables function via another component before replacement. Follow the procedures as documented in the Electrical Maintenance and Troubleshooting manual for the identified component.

How do we avoid this problem from occurring in the future? During regular preventive maintenance procedures, inspect robot and controller components for damaged cable insulation and/or excessive twisting, etc. and replace excessively worn or damaged components. If the failure has occurred, then the failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.

SRVO - 050 / COLLISION DETECTION ALARM

Background: 
This alarm occurs when the amount of energy being returned to the amplifier exceeds the ability to discharge that energy through the discharge resistors circuit.
Solutions: 

Recover is a three step process:

  • Component Failures - Causes of this alarm can be a failed discharge resistor, shunting transistor on-board the amplifier, or motor cable damage where two phases are shorted to each other. A failed motor that presents virtually no load on the amplifier is another way of inducing this alarm. Follow the procedures as documented in the Electrical Maintenance and Troubleshooting manual for the identified component. The failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.
  •  A "non-hardware" way to cause this alarm is to apply the robot in an application that is loaded over its maximum specifications and/or operated in a fast moving motion in excess of the robot duty cycle specification. If the robot is very rapidly decelerated, the braking process floods the amplifier with a large amount of energy in a very short time, and the alarm is generated. The robot application should be reviewed to determine how to reduce robot end-of-arm tool load and center of gravity, and to reduce the magnitude of the accelerations or decelerations required to meet application cycle times.
     

SRVO - 045 HIGH CURRENT ALARM

Background: 
This alarm occurs when the amount of energy being returned to the amplifier exceeds the ability to discharge that energy through the discharge resistors circuit.
Solutions: 

 

  • Component Failures - Causes of this alarm can be a failed discharge resistor, shunting transistor on-board the amplifier, or motor cable damage where two phases are shorted to each other. A failed motor that presents virtually no load on the amplifier is another way of inducing this alarm. Follow the procedures as documented in the Electrical Maintenance and Troubleshooting manual for the identified component. The failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.
  •  A "non-hardware" way to cause this alarm is to apply the robot in an application that is loaded over its maximum specifications and/or operated in a fast moving motion in excess of the robot duty cycle specification. If the robot is very rapidly decelerated, the braking process floods the amplifier with a large amount of energy in a very short time, and the alarm is generated. The robot application should be reviewed to determine how to reduce robot end-of-arm tool load and center of gravity, and to reduce the magnitude of the accelerations or decelerations required to meet application cycle times.

 

SRVO - 046 OVER CURRENT ALARM

Background: 
This alarm occurs when the amount of energy being returned to the amplifier exceeds the ability to discharge that energy through the discharge resistors circuit.
Solutions: 

 

  • Component Failure - Some of the more common causes of this alarm are a failed power transistor in the amplifier, motor cables that have shorted to ground, or a failed motor brakes, or a failure in the brake control circuitry. Follow the procedures as documented in the Electrical Maintenance and Troubleshooting manual for the identified component. The failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.
  • This alarm can also result from a collision where the robot continues to "push" against a fixed object.

 

MY CONTROLLER WON'T BOOT UP

Background: 
The most common description of this failure is that the robot will power up for just a moment, and then automatically "powers-down". The power on/off circuitry uses 24 volts DC, which is the same voltage used for emergency stops, over-travel, and I/O sub-system circuits. If a failure in one of these sub-systems causes the 24v supply to be shorted or overloaded, then the power on/off circuit fails to fully latch ON causing the "power-down" condition.
Solutions: 

The most common causes of this failure are a shorted "EE Cable" ( the cable that connects the end-of-arm tooling to the robot) or a failed "hand broken" circuit (a switch circuit detecting that an end-of-arm tooling safety joint has been upset). Repair the EE Cable and/or re-set the safety joint, and follow robot start-up procedures. If it is determined that other causes exist, then follow the procedures as documented in the Electrical Maintenance and Troubleshooting manual to identify and replace the failed component. The failed/replaced components may be returned to FANUC Robotics for failure analysis and repair for a reasonable cost.

I NEED THE PREVENTATIVE MAINTENANCE SCHEDULES FOR MY ROBOT

Background: 
How often should preventative maintenance be done on my robot?
Solutions: 

The preventive maintenance schedules, as well as the FANUC recommended lubricants, can be found in the robot specific mechanical unit maintenance manuals. Most users ask if a specific lubricant known as "Molywhite" has a domestic substitute. Unfortunately, no domestic substitute exists at this time.

I AM HAVING DIFFFICULTY USING OLPC/OLRP OFFLINE PRODUCTS

Background: 
Having problems with offline software?
Solutions: 

OLPC is an acronym for Off Line Programming for Computers. OLRP is an acronym for Off Line Robot Programming.

  • OLPC is a product for computers that allows the user to edit and compile applications and programs written in the FANUC Robotics programming language known as "Karel".
  • This product is system software version specific. Some problems are experienced when a version of OLPC is used that is different from the system version of the robot.
  • OLRP is a product for computers that allows users to manipulate teach pendant programs for "TPP programs". TPP is the standard type of robot programming for nearly all RJ series controllers. TPP is a "point-and-shoot" interface that creates programs in an already executable format. OLRP allows users wish to download these executables, convert them to an ASCII format, modify these programs, and convert them back into executable form. OLRP is also version specific, just like OLPC. The two most common issues customers report with OLRP are version mismatches, and failed attempts to manipulate TPP programs that have had their TPP environment "Customized". On customized application certain instructions are not recognized by the OLRP translator resulting in failed compilation, since OLRP only recognizes standard TPP instructions.
  • Both OLPC and OLRP products are used by customers on a wide variety and generations of personal computers and operating systems. Since no two computers are identical, computer hardware and environment issues are also applicable to both products and may not perform as expected on some computers and operating systems.
     
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