Manual > Function Description

Important Interfaces

The table below lists only important interfaces. For other interfaces, please refer to “Reference”.

Most important column

〇: Communication is possible using only these

Items without a circle: Important in some cases

Items not listed in the table: Not essential but useful

Important
〇: Important, check it out

Items without a circle: Important in some cases

Items not listed in the table: Not essential but useful

Method Properties		Most Important	important
■ Communications
Connect/DisConnect	Connect/disconnect to PLC.		○
StartUpdate/StopUpdate	Start/stop automatic cache refresh.		○
ReadVal	Read the value.	○	○
ReadVals	Read the values of multiple tags.		○
WriteVal	Write a value.	○	○
WriteVals	Write the values of multiple tags.		○
GetVal	Reads a tag value from the cache.	○	○
■ Tag registration/cancellation
AddUnit	Register the unit (PLC).
DelUnit	Unregister the unit (PLC).
AddFolder	Register a folder.
DelFolder	Unsubscribe from a folder.
AddTag	Register a tag.
DelTag	Unregister a tag.
ClearAll	Delete all units, folders, and tags.
LoadFile/SaveFile	Read/write tag settings files.
■ Error handling
ErrCode	The most recent error code that occurred.	○	○
ErrMessage	The most recent error message that occurred.	○	○
event
ValueStateChanged	Occurs when value and value quality change.		○
ValueChanged	Occurs when the value changes.	○	○
ValueBitOn	Occurs when the bit turns on.
ValueBitOff	Occurs when a bit goes Off.
ValueRefresh	Occurs each time periodic communication for automatic updates is completed.
StateChanged	Occurs when the unit's device down state changes.		○
ErrorOccured	An event that occurs when an error occurs.	○	○

General program processing flow

The general programming process is as follows:

	Register a tag. Tags are set in the tag editor. You can also add tags directly from within a program using the AddTag method.

	Connects to PLC. The connection word enables communication methods such as ReadVal/WriteVal.

	Calling the StartUpdate method will start the automatic update and when the value changes, the ValueChanged event will be raised.

	Reading and writing are done by calling methods. On-demand reading and writing in response to button operations can be done this way.

	Normally, you do not need to worry about closing the form, as the termination process is performed automatically when you close the form.