Omron NT15S, Руководство по эксплуатации

Страница: 167 / 233

153
Standard Mode
Section 4-9
4.9.2.3.4 Information about the Serial Message System
How do messages reach the terminal?
In the controller, a word variable, as a part of the cyclic poll area, is reserved for the
message number. This variable is polled by the operating terminal. If the variable
value is greater than zero, this indicates that this is a numeric value of a message,
i.e. the message number. The message number is placed into the terminal’s mess-
age memory and the variable in the controller is overwritten with zero. This is treat-
ed as the acknowledgement for the controller that the terminal has fetched the
message. The next serial transfer of messages can now take place.
How is a new message recognized?
By flashing of the Help key or by a flashing function key, the terminal signals to the
operator that a new message has been received. This visual indication only ap-
pears when a value has dropped below a limit (message priority for direct display).
How is the message mask configured?
The message mask is preceded by an I/O mask, the configuration mask, and out-
put formats can be defined in it by means of various system variables.
How can the most current messages be output in any chosen I/O mask?
A system variable RepoutRepText is available which always contains the mes-
sage most recently received or the one with the highest priority. The content is
retained up to the next change. The output is always left-justified and as defined in
the configuration menu. There are also the following system variables for complete
or multiple-line output:
RepoutRepText21
RepoutRepText41
RepoutRepText61
See description of the system variables for more information.
Where are messages displayed?
In the message mask. The message mask can be reached via the node mask, the
I/O mask, control keys or soft keys.
Owing to the fact that many control keys are used in the message mask, it can only
be exited by pressing the Home key or function keys.