For newer robots, the Z-axis and Theta-Axis motors have absolute encoders. These devices accurately retain the position of their associated axes even when the robot is powered down. For this function, the encoders must be provided with power from a battery when AC power to the robot is off. This battery is located in the controller section behind the X-axis beneath the rear cover. This battery should provide 3 years of backup power to the absolute encoders with the robot powered off. If this battery voltage drops to a certain threshold, the system generates a warning message on the console stating “Low battery voltage.” At this point the battery should be replaced within one or two weeks.
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| Electrical Shock Hazard | |
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Contact with electrical power can cause serious personal injury or death .The Guidance 3400, the PrecisePower Intelligent Motor Power Supply, and the 24 VDC power supply are open-frame electrical devices that have exposed unshielded high voltage pins, components and surfaces. In addition, the motor power supply provides up to 320 VDC volts and takes about 2 minutes to bleed down after power is disconnected.
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The following are the instructions for replacing the battery.
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1. |
After AC power has been off for a sufficient period to permit the high voltage capacitors to bleed down, remove the rear cover of the X-axis to expose the control components. |
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2. |
The encoder battery is a C cell plugged into one of two pigtail connectors in a short harness that plugs into the controller. Plug a new C cell into the free pigtail connector first, then unplug the old battery. This procedure ensures that battery power is always connected to the encoders and avoids needing to reset the zero position of the absolute encoders. |
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3. |
Replace the rear cover of the X-axis. |