IDEC High Performance Series - Manual (Page 1237)

WindO/I-NV2 User’s Manual 29-3
2 Digital I/O Units
29
Expansion Modules
2.1 Using Digital I/O Units
The inputs and outputs on the digital I/O units are mapped to internal memory locations within the MICRO/I. The
inputs are mapped to LEX bits, while the outputs are mapped to LEY bits. These internal bits are used to monitor the
inputs and control the outputs.
The LEX and LEY bits are octal-based, meaning that only numbers 0-7 are used in their addresses.
Addresses are assigned in ascending order from Slot 1. However, if a unit has four input/output ports, addresses 0 to
3 are assigned to each, and addresses 4 to 7 cannot be used.
2.2 Digital I/O Unit Operation
Digital I/O units can be controlled by switch parts, command parts and scripts. Processing priority should be
determined based on the application.
■ Priority to display processing
In this mode, priority is given to the display and parts processing.
This mode can be used for applications where the priority is on the processing speed of screen parts operation and
screen switching.
Read and write to the HG Digital Input (LEX) and HG Digital Output (LEY) using switch parts, command parts, and
scripts.
Users should understand that the processing time for drawing objects and communicating (the scan time of the
screen) affects the control timing of the digital I/O unit.
This means a time-consuming display process will slow the control time down and result in delayed input response.
■ Priority on control processing
This mode places priority on control processing speed.
It can be used for screens where parts operation is minimal but have many data processing parts.
Use the Cyclic Script to read and write to the HG Digital Input (LEX) and HG Digital Output (LEY).
Refer to “3 Cyclic Script” on page 29-9 for programming information.
Use the Cyclic Script, which executes in conjunction with the digital I/O unit, to provide I/O control at fixed intervals
independent of the scan time of the screen.
2 Digital I/O Units
HG3G HG2G-5F HG2G-5S HG2G-S HG4G HG1F HG2F HG2S HG3F HG4F
Inputs and outputs of digital I/O units can also be controlled and monitored using the word devices WLEX
and WLEY. WLEX and WLEY are useful for batch control of inputs and outputs. For details, refer to Chapter
32 “Internal Devices” on page 32-1.