SMC Networks LECSB Series, Operation Manual

Page: 349 / 423

14 - 12
14. 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 in
programmable
controller
Servo-on
(SON)
ABS transfer mode
(ABSM)
ABS request
(ABSR)
ABS transmission
data ready
(ABST)
Transmission (ABS) data
During transfer of ABS
Lower
2 bits
Checksum
Upper 2 bits
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 PC or PLC...etc 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 transfer mode (ABSM), the servo detects and calculates the absolute position
and turns ON the ABS transmission data ready (ABST) to notify the programmable PC or PLC...etc
that the servo is ready for data transmission.
3) After acknowledging that the ready to send (ABST) has been turned ON, the programmable PC or
PLC...etc 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 ABS
transmission data ready (ABST) in the OFF state.
5) After acknowledging that the ABS transmission data ready (ABST) has been turned OFF, which
implies that 2 bits of the ABS data have been transmitted, the programmable PC or PLC...etc reads
the lower 2 bits of the ABS data and then turns OFF the ABS request (ABSR).
6) The servo turns ON the ABS transmission data ready (ABST) so that it can respond to the next
request.
Steps 3) to 6) are repeated until 32-bit data and the 6-bit checksum have been transmitted.
7) After receiving of the checksum, the programmable PC or PLC...etc confirms that the 19th ABS
transmission data ready (ABST) is turned ON, and then turns OFF the ABS transfer mode (ABSM). If
the ABS transfer mode (ABSM) is turned OFF during data transmission, the ABS transfer mode
(ABSM) is interrupted and the ABS time-out warning (AL.E5) occurs.
PC or PLC...etc
(Pin 17)
(Pin 18)
(Pin 25)
(ABSB0:Bit0) (Pin 22)
(ABSB1:Bit1) (Pin 23)