SMC Networks LECSB2-T Series - Page 427

12. ABSOLUTE POSITION DETECTION SYSTEM
12 - 15
5) SON off, RES on, and EM2 off check during the ABS transfer
When the ABS transfer mode is turned on to start transferring and then SON is turned off, RES is
turned on, or EM2 is turned on before the 19th ABST is turned on, [AL. E5 ABS time-out warning]
occurs, regarding it as a transfer error.
OFF
ON
OFF
ON
OFF
ON
1 2 3 4 18 19
1 2 3 4 18 19
OFF
ON
Yes
No
ABSM
ABSR
ABST
[AL. E5]
SON
(b) Checksum error
If the checksum error occurs, the programmable PC or PLC...etc should retry transmission of the
absolute position data.
Using the ladder check program of the programmable PC or PLC...etc, turn off ABSM. After a lapse
of 10 ms or longer, turn off SON (off time should be longer than 20 ms) and then turn it on again.
If the absolute position data transmission fails even after retry, process the ABS checksum error.
The start command should be interlocked with ABST to disable positioning operation when an
checksum error occurs.
The following shows an example of three retries.
20 ms
or longer
OFF
ON
OFF
ON
OFF
ON
OFF
ON
10 ms
or longer
20 ms
or longer
20 ms
or longer
Retry 1 Retry 2 Retry 3
10 ms
or longer
10 ms
or longer
10 ms
or longer
SON
Yes
No
ABSM
ABSR
ABST
ABS checksum error