Omron SYSMAC C1000H, Руководство по эксплуатации

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Cycle time (ms) Possible adverse affects
10 or greater TIMH(15) inaccurate when TC 048 through TC 511 are used.
20 or greater 0.02-second clock pulse not accurately readable.
100 or greater 0.1-second clock pulse not accurately readable and Cycle
Timer Error Flag (25309) turns ON.
200 or greater 0.2-second clock pulse not accurately readable.
6,500 or greater FALS code 9F generated regardless of watchdog timer setting
and the system stops.
6-2 Calculating Cycle Time
The PC configuration, the program, and program execution conditions must
be taken into consideration when calculating the cycle time. This means tak-
ing into account such things as the number of I/O points, the programming
instructions used, and whether or not peripheral devices are employed. This
section shows some basic cycle time calculation examples. To simplify the
examples, the instructions used in the programs have been assumed to be
all either LD or OUT. The average execution time for the instructions is thus
0.6
µ
s. (Operating times are given in the table in Section 6-1. )
6-2-1 I/O Units Only
Here, we’ll compute the cycle time for a PC that controls only I/O Units, six
on the CPU Rack and eight on an Expansion I/O Rack. In this PC configura-
tion, there is also a Programming Console mounted to the CPU that needs to
be taken into consideration. The PC configuration for this would be as shown
below. It is assumed that the program contains 20,000 instructions requiring
an average of 0.6
µ
s each to execute.
CPU Rack
Expansion I/O Rack
32-point Output Units
16-point Output Units 32-point Input Units
16-point Input Units
16-point Input Units
16-point Output Units
The equation for the cycle time from above is as follows:
Cycle time = overseeing time
+ output refreshing and Unit servicing time
+ input refreshing time
Calculations
Calculating Cycle Time
Section 6-2