Cpu11-E Cycle Time - Omron C200H Operation Manual

Cycle Time
1, 2, 3... 1.
Operation
1. Overseeing
2. Program
execution
3. Cycle time
calculation
4. I/O refreshing
5. Host Link Unit
servicing
6. Peripheral device
servicing
7. SYSMAC LINK and
SYSMAC NET Link Unit
servicing
Special I/O Units in Remote
I/O Slave Racks
Watchdog Timer and Long
Cycle Times
The first three operations immediately after power application are performed
only once each time the PC is turned on. The rest of the operations are per-
formed in cyclic fashion, with each scan forming one cycle. The cycle time is
the time that is required for the CPU to complete one of these cycles. This
cycle includes basically seven types of operation.
Overseeing
2. Program execution
3. Cycle time calculation
4. I/O refreshing
5. Host Link Unit servicing
6. Peripheral device servicing
7. SYSMAC LINK and SYSMAC NET Link Unit servicing
The cycle time is the total time required for the PC to perform all of the above
operations, in the order 4, 5, 6, 7, 1, 2.
Time required
3.5 ms
Total execution time for all instructions varies
with program size, the instructions used, and
execution conditions. Refer to 6-3 Instruction
Execution Times for details.
Negligible
µ µ
70 s per input word. 40 s per output word.
1.3 ms per Remote I/O Master Unit + 0.2 ms
per Remote I/O Slave Unit number used.
Refer to the tables in 6-1-1 CPU01-E, 03-E
Cycle Time for details on PC Link and Spe-
cial I/O Unit refresh time.
8 ms max. per unit
0 ms when no devices are mounted.
0.8 ms when T < 13 ms.
T x 0.06 ms when T > 13 ms.
(T is the total cycle time calculated in opera-
tion 3.)
1.5 ms per unit + 10 ms max.
Remote I/O Master Units are serviced only once each cycle. When Special
I/O Units are mounted in Remote I/O Slave Racks, the Remote I/O transmis-
sion time may exceed the cycle time. There may be cycles in which there is
no I/O refresh between the Master and the PC. Inaccurate signals may be
sent, especially when differential instructions are turned ON and OFF.
Within the PC, the watchdog timer measures the cycle time and compares it
to a set value. If the cycle time exceeds the set value of the watchdog timer,
a FALS 9F error is generated and the CPU stops. WDT(94) can be used to
extend the set value for the watchdog timer.
Function
Watchdog timer set. I/O Bus, Program
Memory checked. Clock refreshed.
Program executed.
Cycle time calculated. When the Cycle
Time instruction (SCAN(18)) is executed,
waits until the set time has elapsed and
then resets the watchdog timer.
Input bits set according to status of input
signals. Output signals sent according to
status of output bits in memory.
Inputs and Outputs in Remote I/O Systems
refreshed.
Special I/O Units serviced.
Commands from computers connected
through Rack-mounting Host Link Units
processed.
Commands from Programming Devices
and Interface Units processed.
Commands from computers connected
through Rack-mounting Host Link Units
processed.
Section 6-1
225