Alarm BZAL and BLAL

  • Hi All Master Fanuc,


    My robot need change battery 4D per week because alarm BLAL and BZAL. Already chenge 4 times. Ask fanuc company they say need to change all internal cable and cost very high because this old robot and controller RJ1. Any suggestion how to trace this problem.


    Thanks all..

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  • As far as tracking down what and where the problem is, i would probably go about it something like this.


    1. Are the batteries actually dead when the robot says they are dead? Remove the batteries and check with a multimeter. If the batteries are good, then there is something wrong with the detection. If the batteries are dead, then there is probably a short that is killing the batteries but not killing the robot/fuses/boards.


    2. If batteries are reading good even with BZAL alarm, take a good backup and document all joint angles and cycle power with the BZAL alarm active. If you loose encoder data, then the batteries are not able to connect to the pulse coders. If you maintain values, then the batteries are doing their job even though they are not being detected.


    3. That should help narrow it down to a rough circuit in the robot/controller/cables. I am not an electrician, and not an expert on electrical systems, but from that you may be able to use the electrical diagrams in the manuals to identify the most likely areas for issues.


    In general, you should check all cables for visually apparent damage, ensure all plugs are fully plugged, and check your fuses. Boards are generally okay unless there is an external stimulus that moves them outside of their normal operating parameters, like a voltage spike or a weld ground fault, and the fuses are intended to protect against most of that. If there is an electrical failure, it is usually in a moving part. Cables are the most likely culprit. If you are keeping data on the robot side, it is more likely to be a cable in the controller or between the controller and the robot, rather than one inside the robot, but that is no guarantee.

  • To add into Robo_Eng_13 I would think if it's just one axis cable causing the issue you should only lose your pulse on that axis alone when you cycle the power narrowing it down to which axis is causing the issue. Thus making it easier to know where to look. It's likely that it is a pinched cable inside the robot. I'm assuming when you get the alarm it is usually in the same position? If so see which axis is closest to it's limit and start there. I would also look at the terminals inside the battery access panel and make sure the prongs are all clean and clear of corrosion and wear and maybe bend them out just a bit to make sure the batteries are making good contact with them.

    "I could tell that my parents hated me. My bath toys were a toaster and a radio."

  • Adding to the great advise in previous posts: Make sure the screws on the back of the battery box are tight and the box is dry and free of corrosion and debris both inside and out. Make sure connector RP1 at the robot base and all the PulseCoder connections are also dry and free of corrosion and debris both inside the connector and in the back of it.


    Excessive current draw from a bad PulseCoder or wire may require a savy electrical/electronic person to track down.


    Use industrial grade batteries and verify the voltage (1.6V-1.65V) of each battery before installation. DO NOT use a battery if it has been dropped.

  • Adding to the great advice in the previous post above: Check that the batteries are being installed correctly. Multiple times and places where i went to a customer site to find out that the batteries were put all positive side/negative side facing in. Instead of the correct polarity/side.

  • I want to add to the great advice! When checking RP1 and RM1 robot cables, make sure that none of your pins or sockets have slipped out of the connector. This happened to me once a while back, and took me a long time to track down...

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