Omron CJ2 CPU UNIT SOFTWARE User Manual

10-93
10 CPU Unit Functions
CJ2 CPU Unit Software User’s Manual
10-8 Synchronous Unit
Operation
10
10-8-5 Restrictions in Using Synchronous Unit Operation
Note The above times are the same as the synchronous processing time minus the normal processing time per-
formed during that time.
z Scheduled Interrupt Tasks 0 and 1 Disabled
If synchronous unit operation is used, scheduled interrupts 0 and 1 cannot be used to execute inter-
rupt tasks. Thus, scheduled interrupt task 0 (interrupt task 2) and scheduled interrupt task 1 (inter-
rupt task 3) cannot be used. Interrupt task 2, however, is used as the synchronous interrupt task.
z Restrictions for Interrupt Control Instructions
The MSKS, MSKR, and CLI instructions cannot be used in the synchronous interrupt task. The DI
and EI instructions can be used.
z Restrictions for Timer Instructions
The following restrictions apply to using the HUNDRED-MS TIMER (TIM/TIMX(550)), TEN-MS
TIMER (TIMH(015)/TIMHX(551)), and ONE-MS TIMER (TMHH(540)/TMHHX(552)) instructions.
• An error of up to one cycle time will occur in the timer PV accuracy.
• The timers will not operate correctly if the cycle time exceeds 100 ms.
• If one of the above instructions is in a task that is stopped or is not executed because it is jumped
by a JMP(004), CJMP(510), or CJPN(511) instruction, the timer will not operate correctly.
z Restrictions on Using Instructions in Interrupt Tasks When High-speed
Interrupt Function Is Enabled
If using the synchronous unit operation function is enabled, the high-speed interrupt function will be
unconditionally enabled in the PLC Setup. Thus, some instructions, such as network communica-
tions instructions, cannot be used in any interrupt tasks, including the synchronous interrupt task.
For details, refer to 10-2-6 High-speed Interrupt Function.
z Other Restrictions When High-speed Interrupt Function Is Enabled
• Background processing cannot be used in interrupt tasks.
• The data in the following Auxiliary Area words will not be valid: A440 (Maximum Interrupt Task
Processing Time) and A441 (Interrupt Task with Maximum Processing Time).
• The increase of the cycle time cause by using EtherNet/IP tag data links will be even longer.
z Mounting Location for Synchronous Units
Synchronous Units must be mounted on the CPU Rack. They cannot be mounted on Expansion
Racks.
Synchronous unit
operation enabled
Synchronous unit
operation disabled
Increase in normal cycle time
cause by synchronous unit
operation
Synchronous
operation cycle
Synchronous
operation cycle
Internal processing for normal cycle time
Internal processing
for normal cycle time
(1)(2) (2) (2) (2) (1)

Omron CJ2 CPU UNIT SOFTWARE Specifications

General

Brand	Omron
Model	CJ2 CPU UNIT SOFTWARE
Category	Software
Language	English