Hitachi S10VE, User Manual

Page: 328 / 506

11. Operation
11-7
For an input transfer, the external input signal and the remote I/O transfer operation are not
synchronized. For this reason, the input value of the input module is sometimes determined immediately
after the transfer starts. In such a case, the correct input value is not transmitted to the CPU module until
the next transfer cycle, which results in a required transfer time of about twice as much (1.6 to 44 ms).
For an output transfer where the remote I/O is operating asynchronously with the ladder, the ladder
processing results are sometimes determined immediately after the transfer starts. In this case as well,
the correct processing results are not transmitted to the output module until the next transfer cycle,
which results in a required transfer time of about twice as much (1.6 to 44 ms). If remote I/O is
operating synchronously with ladder processing, the transfer time always ends within the time of one
cycle (0.8 to 22 ms).
(3) Ladder processing time
This is the time required to process ladder programs. After a cycle starts, this time becomes the value
specified as the sequence cycle time (from 1 to 999 ms). However, if the ladder program processing
takes longer than the sequence cycle time, the time becomes the processing time for the ladder program.
For an input transfer where the remote I/O is operating asynchronously with the ladder, the input value
from the remote I/O is sometimes transmitted to the CPU module immediately after one sequence cycle
for the ladder program starts. In this case, the correct processing results cannot be obtained until the next
sequence cycle, which results in a required ladder processing time of about twice as much. If remote I/O
is operating synchronously with ladder processing, the time for one sequence cycle is always the same as
the ladder processing time.
(4) Output delay time
This is the response time of the output module. The response time differs depending on the type of
output module, but for transistor-based modules the time is about 0.2 ms, while relay-based modules
have times ranging from about 10 to 15 ms. For details, see S 10mini Hardware Manual I/O Modules
(manual number SME-1-114) or HSC-2100 Hardware Manual I/O Modules (manual number SME-1-
126).
Accurate calculations of a value for the processing time are not possible, but you can calculate an
approximate processing time and maximum processing time as follows:
Approximate processing time = (1) + (2) + (3) + (2) + (4)
= (input delay time) + (remote I/O input transfer time) + (ladder processing time)
+ (remote I/O output transfer time) + (output delay time)
Maximum processing time (remote I/O ladder asynchronous) = (1) + (2) × 2 + (3) × 2 + (2) × 2 + (4)
= (input delay time) + (remote I/O input transfer time) × 2 + (ladder processing time)
× 2 + (remote I/O output transfer time) × 2 + (output delay time)
Maximum processing time (remote I/O ladder synchronous) = (1) + (2) × 2 + (3) + (2) + (4)
= (input delay time) + (remote I/O input transfer time) × 2 + (ladder processing time)
+ (remote I/O output transfer time) + (output delay time)