ABB 07AC91, Руководство по эксплуатации

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Advant Controller AC 31 / Issued: 01.99
5 – 3 Programming
3
5.2 List of variables
5 different types of variables are used in the user program:
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Physical, digital or analog input/output variables
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Internal bit, word or double word flags are used for intermediate calculations in the user
program.
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Indirect bit, word or double word constants.
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Step chains, which enable the simple and safe programming of sequential operations.
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Historical values: certain functions require several program cycles for their execution. So,
for example, during the processing of a time function, the variable TIME is updated in each
cycle, i.e. this variable is an example of an historical value.
Direct access to historical values via the user program is not possible with the 40 and 50
series units.
Comments on historical values:
The maximum number of historical values permissible for a project is 256.
A list of functions with their historical values can be found in the appendix A2.
The historical values of the timer functions are independent of the list of historical values of the
other functions. The number of authorized timer functions is unlimited, however, the number of
timer functions taking place simultaneously is restricted to 42.
Ranges of values
- Bit variables (status 0 or 1)
- Word variables (range of values -32768 to 32767)
- Double word variables (range of values -2147483648 to 2147483647)
- Text (ASCII characters)