Delta DVP-ES3 Series, Operation Manual

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C h a p t e r 11 C P U Mo d u l e O p e r a t i n g P r i n c i p l e
11 - 3
11
11.1.2 I/O Refreshing and Communication Service

Refreshing I/O
The CPU module reads external I/O data periodically or outputs data to an external I/O. Refreshing the
I/O 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
All I/O refreshing executes in the same loop. The data in an input device refreshes before a program
executes, and the data in an output device refreshes after the program executes.
Unit Maximum data exchange Data exchange area
Digital I/O module
Depends on the number of input/output
channels in the unit.
Input relay/Output relay
Analog I/O module
Depends on the number of input/output
channels in the unit.
Data register
Network module Depends on the unit. Data register

Communication service
Communication service is the unscheduled communication service for a network module. It includes the
communication requests sent from external equipment to a CPU module, and the communication requests
sent from the CPU module to the external equipment.