Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 533)

Bit & Word Mnemonics
D-iii
Sub-Element Word and Bit Mnemonics
Certain SLC 500 data file elements are made up of multiple words. For example,
Timer and Counter elements use 3 words each, where ST file elements use 42 words
each. (Refer to
Appendix C - Data File Organization and Addressing in the Instruction
Set Reference for more information.) In order to address individual sub-elements or
bits within these multi-word data types, you must use word or bit mnemonics.
Reserved mnemonics may be delimited in the manner described on the previous page
for sub-element words or bits, but cannot be used in conjunction with the (_) character
at the end of a symbol name. For example, in the symbol name SYM_1_ACC, the
“_ACC” portion is a reserved mnemonic and will be truncated during address parsing.
If you want to use the letters of a reserved mnemonic in a symbol name, you could use a
dash ( - ) instead of a space or underscore (_). For example, if you wanted to use the
letters LS to signify Limit Switch in a symbol name rather than the HSC Interrupt Lost
Bit (.LS), you would use a symbol like TEST-LS rather than TEST_LS.
The following is a list of reserved sub-element (w) and bit (b) mnemonics:
Timer Counter Control
Control
(MicroLogix HSC)
.ACC (w) .ACC (w) .POS (w) .HP (b)
.PRE (w) .PRE (w) .LEN (w) .LP (b)
.EN (b) .CU (b) .EN (b) .IB (b)
.TT (b) .CD (b) .EU (b) .IN (b)
.DN (b) .DN (b) .DN (b) .IH (b)
.OV (b) .EM (b) .IL (b)
.UN (b) .ER (b) .PE (b)
.UA (b) .UL (b) .LS (b)
.IN (b) .IE (b)
.FD (b)