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1.4 REPLACING BATTERY FOR ABSOLUTE PULSECODERS
• When the voltage of the batteries for absolute Pulsecoders becomes low, alarm 307 or 306 occurs, with the following
indication in the CNC state display at the bottom of the CNC screen.
Alarm 307 (alarm indicating the voltage of the battery becomes low) :
The indication "APC" blinks in reversed display.
Alarm 306 (battery zero alarm) :
The indication "ALM" blinks in reversed display.
• When alarm 307 (alarm indicating the voltage of the battery becomes low) occurs, replace the battery as soon as possible. In
general, the battery should be replaced within one or two weeks, however, this depends on the number of Pulsecoders used.
• When alarm 306 (battery zero alarm) occurs, Pulsecoders are reset to the initial state, in which absolute positions are not
held. Alarm 300 (reference position return request alarm) also occurs, indicating that reference position return is required.
• In general, replace the batteries periodically within the service life listed below.
- A06B-6050-K061 or D-size alkaline dry cells (LR20) : Two years (for each six-axis configuration)
- A06B-6073-K001 : Two years (for each three-axis configuration)
- A06B-6114-K504 : One year (for each three-axis configuration)
The above values indicate the estimated service life of batteries used with FANUC absolute Pulsecoders.
The actual battery service life depends on the machine configuration based on, for example, detector types.
For details, contact the machine tool builder.
1.4.2 Replacing Batteries
To prevent absolute position information in absolute Pulsecoders from being lost, turn on the machine power before replacing
the battery. The replacement procedure is described below.
<1> Ensure that the power to the servo amplifier is turned on.
<2> Ensure that the machine is in the emergency stop state (the motor is inactive).
<3> Ensure that the DC link charge LED of the servo amplifier is off.
<4> Detach the old batteries and attach new ones.
The replacement of the batteries in a separate battery case and the replacement of the battery built into the servo amplifier are
described below in detail.
The absolute Pulsecoder of each of the
S series servo motors and the
S series servo motors (
S22) has a built-in backup capacitor. Therefore, even when the power to the servo amplifier is off
and the batteries are replaced, reference position return is not required if the replacement completes within
less than 10 minutes. Turn the power on and replace the batteries if the replacement will take 10 minutes or
To prevent electric shock, be careful not to touch metal parts in the power magnetics cabinet when replacing
Because the servo amplifier uses a large-capacitance electrolytic capacitor internally, the servo amplifier
remains charged for a while even after the power is turned off. Before touching the servo amplifier for
maintenance or other purposes, ensure your safety by measuring the residual voltage in the DC link with a
tester and confirming that the charge indication LED (red) is off.
Be sure to replace the batteries with specified ones. Pay attention to the battery polarity. If a wrong type of
battery is used or a battery is installed with incorrect polarity, the battery may overheat, blow out, or catch
fire, or the absolute position information in the absolute Pulsecoders may be lost.
Ensure that the battery connector is inserted in the correct position.