Omron CPM2C

18
Structure and Operation Section 1-3
1-3-5 Cyclic Operation and Interrupts
Basic CPU Operation Initialization processing is performed when the power is turned ON. If there
are no initialization errors, the overseeing processes, program execution, I/O
refreshing, and communications port servicing are performed repeatedly
(cyclically).
The cycle time can be read from a Programming Device.
AR 14 contains the maximum cycle time and AR 15 contains the present
cycle time in multiples of 0.1 ms.
Startup initialization
Overseeing
processes
Program execution
Cycle time
calculation
I/O refreshing
RS-232C port
servicing
Peripheral port
servicing
• Check hardware.
• Check memory.
• Read data from flash memory (program,
read-only DM data, and PC Setup settings).
• Check for battery error.
• Preset the watch (maximum) cycle time.
• Check program memory.
• Refresh bits for expansion functions.
• Execute the program.
(Refer to the Programming Manual (W353) for
details on cycle time and I/O response times.)
• Wait for minimum cycle time if a minimum
cycle time has been set in the PC Setup
(DM 6619).
• Calculate cycle time.
• Read input data from input bits.
• Write output data to output bits.
• Perform RS-232C port communications
processing. (Can be changed in DM 6616.)
• Perform peripheral port communications
processing. (Can be changed in DM 6617.)
PC cycle time