Automatic control function programming manual ladder language

3.4 Mnemonic
A mnemonic is a combination of up to twelve characters at most chosen from:
- the 26 capital letters (A, B, C, ..., Z),
- the 26 lower case letters (a, b, c, ..., z),
- the 10 digits (0, 1, 2, ..., 9),
- the underline character ( _ ).
A mnemonic must always begin with a letter (the underline character is prohibited). The compiler does not differentiate
between upper and lower case letters. The user can only associate a mnemonic with a variable %.
These associations are saved in the PLCTOOL symbol files (*.XSY).
3.4.1 Coercion Field
When using a mnemonic, the variable size specified can be different from that indicated when associating the
mnemonic with a % variable.
Coercion is specified after the mnemonic by a dot (.) followed by the symbol for the new size.
Example
If the mnemonic «Status_word» is associated with variable %M3.B,
Then: The mnemonic «Status_word.0» represents %M3.0
The mnemonic «Status_word.7» represents %M3.7
The mnemonic «Status_word.W» represents %M3.W
The mnemonic «Status_word.L» represents %M3.L
3.5 Common Internal Variables Saved
These are variables from %M0 to %M77FF (i.e. 30 kbytes).
These %M variables are saved in case of a power failure.
3.6 Common Internal Variables Not Saved
These are variables %V0 to %V7FFF (i.e. 32 kbytes).
These %V variables are not saved in case of a power failure or a CPU INIT. They are reset by reset of the central
processing unit.
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