Chapter 4 CPU Specifications
XBC E-Type Main Unit 4-8 Ver. 1
The main unit executes the scan in the following order. A user can estimate the control performance of a system
constructed from the following calculation.
Scan time = ① Scan program process ＋ ② System check & Task process ＋ ③I/O data Refresh
+ ④ Network Service + ⑤ XG5000 Service + ⑥ User Task Program process
① Scan program process = no. of instruction x process speed per each instruction (refer to XGK/XGB instruction
user manual)
② System check & Task process: 600 ㎲ ~ 1.0ms [varies depending on the usage of auxiliary functions]
③ XG5000 Service process time: 100 ㎲ at the max data monitor
④ Task Program process time: sum of task processing time that occurs within a scan; the time calculation by
task programs are as same as that of scan program.
⑤ XG5000 processing time: 100 ㎲ during maximum data monitoring. When changing monitor screen, scan time
increases; when using USB Max. Write: 6ms. When using USB Normal Write: 1.6ms.
⑥ Task program process time (not shown in drawing). Task processing time will vary depending on actions of
the task program. Time calculation for each task program is the same as scan time calculation.
2. Example
The scan time of a system consisting of main unit (program 4kstep) + five 32-point I/O modules + one analog
module + one communication modules (200 byte 1 block)
Scan time(㎲) = ladder execution time + system processing time + digital module I/O processing time + analog
I/O processing time + communication module processing time + XG5000 Service processing time
= (2047 x (0.67(LOAD)+ 0.80(OUT)) + (500) + (300 x 5) + (3000 x 1) + (800 x 1) + (100) ㎲
= 3009 + 500 + 1500 + 3000 + 800 + 100 ㎲ = 8909 ㎲
= 8.9 ㎳
(When performing online edits or writing XG-PD parameter, scan time increases temporary up to 100ms)
Data Update
②
System check &
Task processing
④
③
Data exchange
odule
⑤
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