479
Cycle Time
Section 7-3
Note
1.
The number of timers to undergo interrupt processing can be set in DM
6629 of the PC Setup. The default setting is for TC 000 through TC 015.
2.
The PC Setup (DM 6655) can be used to disable detection of CYCLE TIME
OVER error.
3.
The FALS 9F cycle monitoring time can be changed by means of the PC
Setup (DM 6618).
Cycle Time Example
In this example, the cycle time is calculated for a CQM1H with 80 I/O points.
The I/O is configured as follows:
DC inputs: 48 points (3 words)
Bit outputs: 32 points (2 words)
The rest of the operating conditions are assumed to be as follows:
User’s program:
2,000 instructions
(consisting of LD and OUT instructions)
Inner Boards:
Serial Communications Board and
High-speed Counter Board
Communications Units: No Controller Link Unit
Clock:
None
RS-232C port:
Used
Cycle time:
Variable (no minimum set)
Note
The average processing time for a single instruction in the user’s program is
assumed to be 0.625
µ
s.
The cycle times are as shown in the following table.
Note
1.
The cycle time can be automatically read from the PC via a Peripheral De-
vice.
2.
The maximum and current cycle time are stored in AR 26 and AR 27.
3.
The cycle time can vary with actual operating conditions and will not nec-
essarily agree precisely with the calculated value.
4.
The RS-232C and peripheral port service time will be 0.256 ms minimum,
65.536 ms maximum.
7-3-2
Instruction Execution Times
The following table lists the execution times for CQM1H instructions. The max-
imum and minimum execution times and the conditions which cause them are
given where relevant. When “word” is referred to in the
Conditions
column, it
implies the content of any word except for indirectly addressed DM words.
Indirectly addressed DM words, which create longer execution times when
used, are indicated by “
*
DM.”
Process
Calculation method
Time with peripheral
device
Time without peripheral
device
Overseeing
Fixed
0.8 ms
0.8 ms
Program execution
0.625
×
2000 (
µ
s)
1.25 ms
1.25 ms
Cycle time calculation
Negligible
0 ms
0 ms
I/O refresh
0.01
×
3 + 0.005
×
2 (
µ
s)
0.04 ms
0.04 ms
RS-232C port servicing
0 ms
0 ms
Peripheral port servicing
Minimum time
0.34 ms
0 ms
Serial Communications
Board servicing
0.4 + 0.26 (ms)
0.66 ms
0.66 ms
Communications Unit
servicing
0 ms
0 ms
0 ms
Cycle time
(1) + (2) + (3) + (4) + (5) + (6)
3.27 ms
3.01 ms
Содержание SYSMAC CQM1H Series
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