Delta Electronics AH500 Operation Manual page 343

10.1.2 I/O Refreshing and Communication Service

I/O refreshing
A CPU module reads external I/O data periodically or output data to external I/O. I/O refreshing includes
the following.

Refreshing data in a digital I/O module

Refreshing data in an analog I/O module

Refreshing data in a network module

Refreshing data in a motion control module
All I/O refreshing is executed in the same loop. The data in an input device is refreshed before a program
is executed, and the data in an output device is refreshed after the program is executed.
Unit
Digital I/O module
Analog I/O module
Network module
Motion control module

Communication service
Communication service is nonscheduled communication service of a network module. It includes the
communication request sent from external equipment to a CPU module, and the communication request
sent from the CPU module to the external equipment.
10.2 Operating Modes of the CPU Module
10.2.1 Operating Modes
There are two operating modes. They can be used to control a user program and all tasks.
STOP mode: A program is not executed under this mode. Users can download a module table, initialize CPU
configuration and other setting, download a program, check a program, and force a bit ON/OFF.
RUN mode: A program is executed under this mode. Users can not download a module table, and initialize
CPU configuration and other setting.
10.2.2 Statuses and Operation under Different Operating Modes
The STOP mode and the RUN mode are modes for a CPU module. The statuses and operation under these
modes are listed below.

Basic operation
CPU
Program
mode
The execution
STOP of the program
stops.
The program is
RUN
executed.
C h a p t e r 1 0 O p e r a t i n g P r i n c i p l e o f t h e C P U M o d u l e
Maximum data exchange
It depends on the number of input/output
channels in the unit.
It depends on the number of input/output
channels in the unit.
It depends on the unit.
It depends on the unit.
I/O
External output
refreshing
OFF (If users set the I/O
module so that the final
state of the external output
The I/O
on the I/O module is
refreshing is
retained, the final state of
executed.
the external output on the
I/O module will be
retained.)
The I/O
The external output is
refreshing is
controlled by the program.
executed.
Data exchange area
Input relay/Output relay
Data register
Data register
Data register
Program memory
Non-latched Latched
area area
The data in the program
memories are retained.
The program memories are
controlled by the program.
1 0 - 3