15 - 10
15. ABSOLUTE POSITION DETECTION SYSTEM
(b) Detailed description of absolute position data transfer
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
3)
4)
5)
7)
(Note)
1)
2) 6)
Servo-on
(programmable
controller)
Servo-on
(SON)
ABS transfer mode
(ABSM)
ABS request
(ABSR)
Send data ready
(TLC)
Transmission (ABS) data
During transfer of ABS
Lower
2 bits
Checksum
Upper 2 bits
12 1819
Note. If the servo-on (SON) is not turned ON within 1 second after the ABS transfer mode (ABSM) is turned ON, an SON
time-out warning (AL.EA) occurs. This warning, however, does not interrupt data transmission.
It is automatically cleared when the servo-on (SON) is turned ON.
1) The programmable controller turns ON the ABS transfer mode (ABSM) and servo-on (SON) at
the leading edge of the internal servo-on (SON).
2) In response to the ABS transfe r mode (ABSM), the servo detects and calc ulates the absolute
position and turns ON the send d ata ready (TLC) to notify the programmable controller that the
servo is ready for data transmission.
3) After acknowledging that the ready to send (TLC) has been turned ON, the programmable
controller turns ABS request (ABSR) ON.
4) In response to ABS request (ABSR), the servo outputs the lower 2 bits of the ABS data and the
ready to send (TLC) in the OFF st ate.
5) After acknowledging that the read y to send (TLC) has been turned OFF, whi ch implies that 2
bits of the ABS data have been transmitted, the programmable controller reads the lower 2 bits
of the ABS data and then turns O FF the ABS request (ABSR).
6) The servo turns ON the ready to send (TLC) so that it can respond to the next request.
Steps 3) to 6) are repeated until 32-b it data and the 6-bit checksum have been tran smitted.
7) After receiving of the sum check, the programmable controller confirms that the 19th ABS
transmission data ready (ABST) i s turned ON, and then turns OFF the ABS tr ansfer mode
(ABSM). If the ABS transfer mode (A BSM) is turned OFF during data transmissio n, the ABS
transfer mode (ABSM) is interrupte d and the ABS time-out warning (AL.E5) occu rs.