Read Coordination Byte; Editing Request Bit (Bit 'Ea'); Editing Status Bit (Bit 'Ez') - Omron NT4S Operation Manual

Standard Mode
4.20

Read Coordination Byte

4.20.1 Editing Request Bit (Bit 'EA')

4.20.2 Editing Status Bit (Bit 'EZ')

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The term Read Coordination Byte indicates that the controller only reads this
byte. It is only written to by the operating terminal.
This byte is used for the handshake and data coordination with the controller. For
this purpose, the terminal reports its current status to the controller in the symbolic
name entered here. Each bit has its own specific function. The structure is as il-
lustrated below:

Read coordination byte

LSB
Editing request flag Bit EA
Editing status flag Bit EZ
Refresh request flag Bit RA
Liveness flag Bit LM
Data set download aktive DDA
not assigned
not assigned
not assigned
Fig. 20: Structure of the Read coordination byte
The Read coordination byte is used to pass the status of the operating terminal to
the controller.
For the functionality of the individual bits refer to the respective chapters.
The terminal supports the
Coordination Byte has also been activated in the cyclic poll area. To activate both
coordination bytes, the size of the poll area and the polling time must be specified
during programming time. In addition, the addresses of the Read coordination byte
and poll area must be specified in the variable list.
The editing request bit is used to signal to the controller that the value of a variable
is to be modified on the terminal. To do so, the operator presses the Data Release
key. The status LED in the Data Release key is flashing as long as the editing
release has not been set by the controller. Once the controller has set the External
Data Release bit in the Write Coordination Byte to logical 1, the status LED in the
Data Release key remains lit and the value can be modified by the operator.
Once the controller has set the editing release, the editing status bit is automatically
set to logical 1 by the terminal. The bit is reset to logical 0 after the Enter key is
pressed by the operator.
0 1 2 3
Read Coordination Byte
Section 4-20
4 5 6 7
function only if the Write
MSB