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14. ABSOLUTE POSITION DETECTION SYSTEM
(2) Transfer method
The sequence in which the base circuit is turned ON (servo-on) when it is in the OFF state due to the
servo-on (SON) going OFF, an emergency stop, or alarm, is explained below. In the absolute position
detection system, always give the serial communication command to read the current position in the driver
to the PC or PLC...etc every time the ready (RD) turns on. The driver sends the current position to the PC
or PLC...etc on receipt of the command. At the same time, this data is set as a position command value in
the driver.
(a) Sequence processing at power-on
OFF
80ms
ON
OFF
ON
OFF
ON
OFF
ON
5ms
ABS data
Power
supply
Base
circuit
Absolute position data
command transmission
Absolute position data
receive
Current position
Pulse train command
Current position change
During this period, get absolute position data.
Servo-on
(SON)
Ready
(RD)
1) 95ms after the servo-on (SON) has turned on, the base circuit turns on.
2) After the base circuit has turned on, the ready (RD) turns on.
3) After the ready (RD) turned on and the PC or PLC...etc acquired the absolute position data, give
command pulses to the drive unit. Providing command pulses before the acquisition of the absolute
position data can cause a position shift.
(b) Communication error
If a communication error occurs between the PC or PLC...etc and driver, the driver sends the error code.
The definition of the error code is the same as that of the communication function. Refer to section
13.3.3 for details.
If a communication error has occurred, perform retry operation. If several retries do not result in a
normal termination, perform error processing.