Toshiba S20LP - Manual (Page 64)

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63
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6 F 3 B 0 3 5 6
Actual transmission cycle time (TCY) is sum of above TSCN and TMSG. But when TSCN is
short, Time for software operation (TSOFT) is not neglected. Therefore, Actual transmission
cycle time is expressed as follows.
If T
SOFT
< T
SCN
/ 2
T
CY
= T
SCN
+ T
MSG
If T
SOFT
> T
SCN
/ 2
T
CY
= T
SCN
/ 2 + T
SOFT
+ T
MSG
T
SOFT
= ( 370 * N
STN
+ 2.8 * W
SCN
) / 1000 [ms]
Set the Target Scan Time (Target Cycle Time) larger than above T
CY
.
Here;
N
STN
: Number of connected stations
W
SCN
: Total size of send data (words)
W
MSG
: Maximum message size of send data (words)
M
STN
: Number of message transmission stations
(Note 1) The minimum T
SCN
is about 3 ms. Even if the above calculation result is less than 3 ms,
actual TSCN is limited by this value.